course


Mar 2021 
Caveat: I took this class in Fall 2019. Yes, this class is everything they say it is. Yes, Florian is one of the most rigorous professors I have had thus far. And yes, I spent hours and hours of my life doing each homework, many of which contained material beyond the scope of what other ODE classes cover. However, the insane difficulty and rigor of this course caused me to put an incredible amount of effort into it out of sheer necessity, which meant I got more out of it than any other math course I have taken here. Florian is a very nice guy and helpful during his OH, which you will almost certainly need to go to (the TAs don't always know how to solve the HW). This course will make you suffer, but it will also leave you wanting to study more math, particularly the pure math side of things; this class is much heavier on the theory than other ODE classes I have seen, so you'll want to take real and complex analysis after being teased with tastes of them here. There is obviously a very large curve in this class due to its sheer difficulty, although it is not particularly generous at the top end (most of the class ended up with a Brange grade), but getting a B required an average in the 50s, if I remember correctly (an A was a 75% or above). Again, this is by no stretch of the imagination an easy class, but it is a very worthwhile one. Florian is very nice and understands the material very well, and I generally think he gives off positive vibes. This class made me personally want to pursue higherlevel mathematics courses, most of which have turned out to be easier than it despite being at the 4000 level.
Jan 2021 
Johne is a piece of work. The sole source of my stress for the majority of the semester. I'll start with the good. This class is conceptually challenging and will force you to learn a lot of ODEs at a very high level. You will cover a lot of proofs. You will become intimately familiar with modeling the harmonic oscillator using an ODE. You will definitely never be bored. Now the bad. Johne is incredibly incompetent. His problem sets are atrocious and sometimes took me upwards of 20 hours. He writes all of his own problems, and they tend to be of the form "prove xyz = abc", which is hellish. Additionally, in 2020, his exams were take home, which sounds kind and forgiving, but in reality, Johne formatted it so instead of a 2hour exam it was a 48hour exam. Exams had millions of parts, were convoluted, and were incredibly difficult. And on top of it all, harshly graded! Finally, Johne's lectures suck. He just does a bad job telling you what is important, what you should write down, and what is irrelevant. His lectures are basically a series of worked examples, with a little theory thrown in. So you always have to go back and decipher his work. In essence, Johne takes an alreadydifficult class and makes it so indecipherable that it doesn't feel real anymore. If this class wasn't required for my major, I would have dropped it.
Dec 2020 
To this day, this class is probably the worst academic experience that I've ever had in my life. Prof. Johne is very nice and willing to help out as much as he can, but his class is way too difficult and the workload is too high. The lectures include extremely long examples and he makes concepts seem way more complicated than they are. If you are taking this course, prepare to selfteach the entire thing. The problem sets are unnecessarily difficult and take way too many hours to complete. The same goes for the exams: they were takehome exams but included 812 questions with 310 subsections each. On the exams, he has a couple of questions that he marks with a bat symbol that are supposed to be more challenging: these problems are practically unsolvable and/or will require you to make sacrifices to Batman and Robin to solve. Based on what I've heard from other students, other professors run much easier ODE courses and Florian's version is particularly difficult and rigorous. Again, he's a really nice guy, but DEFINITELY avoid this section of ODE unless you want to sacrifice your soul for an entire semester.
Jan 2020 
Prof. Daskalopolous / “Toti was an amazing prof for ODE!! I took this the semester after Linear Algebra (which is definitely a prerequisite, aka do not try to take this at the same time as linear) and managed fine. Some people in the class had a more rigorous theoretical background, but it is not absolutely necessary. The course is definitely more proof heavy than its 2030 counterpart, though, from what I’ve heard. Toti was a caring and conscientious professor, and she was very accessible in OH and after class. She is extremely sweet and I felt like she actually cared about my success in her course. Her exams were fair, and she tried to hint at what would be on each (hint: existence and uniqueness!!). She would also occasionally tell us what would NOT be on the exams. The midterm had more theory than I expected, but it wasn’t too bad. And the final material evenly pulled from the entire course material. The midterm was definitely more challenging than the final, which she admitted. Topics covered included first order ODEs, second order and high ODEs, series solutions (review power series!), systems of ODEs (linear algebra applied here), Laplace transforms (incl. impulse functions, step functions, convolution integral). It definitely feels like a lot of material after the midterm. She curved the midterm 10 flat points (post curve avg was in 70s), unsure about curve on the final, but the average was a 65. I finished with an A in the course, scoring 1520 points about the mean on both exams and having nearly full points for homework. Landing in the Arange is definitely achievable for the dedicated student, as the exams directly reflect the notes. Overall, ODE is a wonderful experience with Prof. D. Her great teaching makes it worth the extra difficulty of taking this course vs. 2030.
Dec 2019 
To be fair, I think much of the difficulty I had in this class came from the fact that this being the 3000 level of ODE, I wasn't prepared to compete with a smarter bunch of students than the 2000 level of the course. That being said, she was a good professor and much of the previous reviews about her teaching style continue to remain true. I would definitely argue that this class was slightly difficult, although she did say she to us that she had made the exam harder, thinking that we were a more capable class (not sure what she was talking about in my case). The exams were not easy with the average of the midterm being a 67 (she added ten points to everyone's score for some reason) and the average of the final being a 53. Thus, not impossible, but certainly not easy by math department standards (i.e. somewhere below the ludicrously high averages of calc ii/iii and above the devastating averages in modern algebra and / or analysis). That being said, ODE intellectually can be quite dull at times. I recommend taking the 3000 level to people who need more mentla stimulation because seeing some more proofs and being tested on it while, at times, a bit harder and tedious to memorize the proofs was certainly better than simply chugging through mindless equations that people give to computers in practice nowadays anyway. Overall, I've heard she curves to an A/B+ and wont give out grades lower than a B minus except for extreme circumstances.
Dec 2019 
To be fair, I think much of the difficulty I had in this class came from the fact that this being the 3000level of ODE, I wasn't prepared to compete with a smarter bunch of students than the 2000 level of the course. That being said, she was a good professor and much of the previous reviews about her teaching style continue to remain true. I would definitely argue that this class was slightly difficult, although she did say to us that she had made the exam harder, thinking that we were a more capable class (not sure what she was talking about in my case). The exams were not easy with the average of the midterm being a 67 (she added ten points to everyone's score for some reason) and the average of the final being a 65. Thus, not impossible, but certainly not easy by math department standards (i.e. somewhere below the ludicrously high averages of calc ii/iii and above the devastating averages in modern algebra and/or analysis). That being said, ODE intellectually can be quite dull at times. I recommend taking the 3000 level to people who need more mental stimulation because seeing some more proofs and being tested on it while, at times, a bit harder and tedious to memorize the proofs was certainly better than simply chugging through mindless equations that people give to computers in practice nowadays anyway. Overall, I've heard she curves to an A/B+ and won't give out grades lower than a B minus except for extreme circumstances.
Nov 2017 
I feel as though I am fairly qualified to write a review for Barraquand as I have taken 3 semesters with him so far: Calc III, Linear and ODE. Over all, I think Guillaume is a great teacher in comparison to the rest of the math department. That being said, he is not the best teacher ever. GB is not the best teacher in terms of actual lectures. He sometimes goes on tangents of proofs which are albeit interesting not really relevant to the class. That being said, when discussing actual content he is fairly clear on what to expect and how to approach most problems. In linear particular he was a little confusing, but that was perhaps due to the subject matter rather than himself. His classes are somewhat dry but enjoyable, he cracks a lot of jokes and the class is fun. I think GB is an extremely fair teacher. All his HWs are very fair and his grading gives a lot of partial credit. His test, while difficult ask about the entire scope of the topic. They are very well made and really show if you understand the material. His curves are very generous, the last commenter was accurate in terms of grading. Moreover, since the tests are difficult and the averages are usually in the 50s60s, getting a good grade is a lot easier then meets the eye. I would gladly recommend him to any of my friends.
Jan 2015 
My final impression of this course is a positive one. I found Daskalopoulos to be sweet and accommodating, and the class progressed at a reasonable pace. The majority of the classes were spent first deriving theorems/discussing techniques, and then going over a few examples. Perhaps sometimes she spent too long explicitly writing out each step of a proof, although I she certainly isn't painfully slow. She certainly knows the material and is able to answer any question confidently, understanding common pitfalls that many students have. While working through examples, however, she often makes many algebraic mistakes, although a handful of students who always seem to be paying very close attention always are there to correct her. She makes herself available and approachable, and was receptive to increasing, within reason, students' midterm grades who were graded by an unusually harsh TA. The class itself certainly won't be your favorite math class at Columbia, with material being a toolbox of techniques, such that whenever you see a problem, you must only identify which technique is appropriate and the answer should produce itself. From class to class progress can seem slow, although at the end you do realize that you have covered many techniques. The homework usually was a little more tedious than I would have liked. The examples from the book (Boyce & DiPrima) usually are not too polished, and will often have you writing many pages of algebra for certain problems. I found the problem sets always took between 36 hours a week, so it's not too bad. Having said that, if you do all the homework (which is worth almost nothing) you'll hardly have to study at all for the midterm / final. I thought those tests were extremely reasonable tests, with a perfect score being well within the reach of an attentive, responsible student. You should be familiar with all the aspects of the existence/uniqueness proofs, which apparently tripped up many students. The most helpful way to study for these tests, I found, is to make a study sheet that just lists all the different techniques you've learned and familiarize yourself with them before the test. While not too glamorous, ODEs with Daskalopolous is a pleasant, straightforward experience
Dec 2013 
His lectures are awful (he always looks at the ground, can't understand a word that he's saying) and you will learn nothing from them, but thats okay because this class is easy as fuck. He often repeated questions from practice midterms on exams  like with the same numbers and everything. Do the practice midterms and you will be golden. Weekly problem sets with some dumb problems but what do you expect its a math class. Shoutout to TA Oren who promptly answered my questions via email.
Jul 2013 
This guy is the worse I've ever had, his writing on the board is unreadable, following no logic, lacking any helpful illustration or insight. A teacher should make the complex simple not the other way around. Extremely arrogant at questions, while void of any interest or concern about the student grasp of the topic. This is a disgrace to Columbia, the Ivy League, and the state of our higher learning... Complete scam. When the student sitting next to you can do a way better job than the guy your paying to teach you math, you know something is wrong. He didn't doesn't even take a breath to stop from rambling that a day's material is often covered 20 minutes early before class ends. And it wasn't only me, I talked the others after each class, and they all got the vibe that he wants to see us confused and fail. It's pretty sad, actually. I have nothing to lose by this, I did not get a bad grade in this class, so I'm not just ranting... Conclusion: Drop the course and take it with a wiser instructor, an actual professor of mathematics whose craft of teaching math and encouraging students to becoming mathematician is polished.
Jan 2013 
Prof. Daskalopoulos is definitely one of the sweetest professors I've had in my 1.5 yrs at Columbia personalitywise. She's very approachable during office hours and always responded to my emails in a timely manner. I got kind of sick of the class after a while because it kind of seemed like a recipe book we were memorizing  different methods for solving different types of ODEs. There wasn't much depth, in my opinion. The questions on the tests were either incredibly easy or quite challenging. She LOVES to pose nonconstant coefficient problems, which aren't covered too extensively in the course, so that was pretty nervewracking. Make sure you're comfortable with them... Also, though Linear Algebra is a coreq, I was taking it at the same time and when we got to the section in ODE about linear systems, which involves eigenvalues and diagonalization, we hadn't yet covered that in Linear Algebra, so I had to teach that to myself ahead my Lin Al class. Not too difficult, but not optimal. She also expected us to know a proof which involved a double integral (and I haven't taken Calc IV yet), but she didn't end up asking about it on the exam. In terms of the theory on the exam, it's always pretty elementary stuff that she goes over in class. As long as you take notes and know your notes, you'll be fine.
Dec 2011 
Eh. I was pretty apathetic towards because she was not very clear presenting the material. She is your standard Columbia Math dept professor who does not care too much about teaching undergrads. She'll keep on going through class whether you understand it or not. Frankly, it's not too hard to teach it to yourself, but what's the point of paying your tuition then? I do wish she would give more practice problems for the exams and also POST THE PROBLEM SET SOLUTIONS.
Sep 2011 
Prof Daskalopoulos is a good professor. She followed the text book very closely and explained it well. Her experience teaching this class showed in her explanations and also answering all questions during class. I considered the lectures clear given how difficult the material is. I did well in my calculus classes, but ODE is a step above. Computations can be very long and complicated for some types of problems. Also, She went over some additional proofs that I think were skipped in the engineering version of the class. These were a little rough. But the book also explains everything and helped me out a bit. She is very accessible during her office hours and very patient with all the questions. Like a few other professors, she had one or two questions on her tests that were slightly extended from her lectures and homework. However, even those were just other problems from the end of the problem set in the book that weren't assigned.
Dec 2009 
I agree with most previous reviews: Virdol is a terrible teacher. I disagree with most previous reviews: Virdol is not an excellent mathematician. He doesn't seem to know his stuff at all. He often finds himself not knowing how to proceed in a problem, and during one of the classes actually said "To calculate this integral, you need to use a trick. What it is, I don't know." This was about a question on the practice final; slightly unnerving if you're student in such a class. He mumbles away for an hour and fifteen, occasionally flashing a wry smile that really he has no reason to. Fortunately, doing well in his class is the simplest formula ever. Go over all the practice exams given before any particular exam. Midterm 1 was almost exactly the same as Practice Midterm 1, same with Midterm 2, and the final was a mix of the two practice midterms and the practice final.
Dec 2009 
Be prepared to self study the subject the whole entire semester. Virdol is a good mathematician and picked an excellent textbook for you to study from. There is no point in going to his lectures because he just mumbles incoherently into the board and it is better for you to stumble through the HW problems. The only classes worth going to are the review classes before the midterms and final. If you understand the practice midterm and finals then you are golden for the class. To summarize, in order to do well in the class you only need to do three things: 1) Do the HW, skip classes 2) Memorize the practice midterms/finals 3) Shameless go beg him for points on the midterm/final you just failed during OH right after you get your test back (sucks for you if you failed the final though).
Dec 2009 
Nice enough. Personally, I found her blackboard method very confusing. She's a bit all over the place, but examples come straight out of the text. For someone who lectures straight out of the book, I found it completely frustrating that she threw us so many curveballs on the exams. Her tests feel completely disconnected from the (much more computational and straightforward) material at hand, and the final introduces things we don't cover in class. Basically, people seem to like her and I see whyshe's very open and responsive, and is generous with her time during office hours. But I was pretty confounded by this class.
Dec 2009 
I took ChenYun Lin's class in the summer after having failed (yes failed!) the course in the spring. She's not an actual professor, more like a TA but you can feel the difference  she's smart, fresh, funny and she sometime styles her hair into pigtails. She's also chinese but you can actually understand her because she speaks slow which is a plus. And even though we had only six weeks to cover the course, she would stop if she felt that students were not understanding the material. I actually felt sad when the class was over. Definitely take her if she is teaching a class.
Oct 2009 
Awesome prof, explains material well in lecture. Unlike most other postcalc math classes, reading the textbook doesn't feel like learning everything from scratch. The class is reasonably easy and the material is interesting.
Jan 2009 
This is the first semester I take with Prof. Hou. t has been my best experience in the math department. he is really great. As a previous reviewer points out, he is the most straightforward Prof you'll find in the dept. Also, he is very nice and approachable. I am not particularly great in math, and furthermore when i took this class, i had so much going on, still i was able to do better because his lectures were so clear, and he was very helpful. i would absolutely recommend him to another student, as I think he is the clearest professor i've had. he does a good job in teaching, and he tests on what he teaches, no funky business. I wished i'd taken calc III or IV with him because i would know what those classes are actually about. instead i took those classes with terrible professors that were obsessed with making us learn stuff that wasn't even on the book, as a result i actually ended up learning this stuff in another class that wasn't math. Briefly, my suggestion if you happen to be wondering about any of Prof. Hou's class is that you should absolutely give it a try.
Dec 2008 
Oh my goodness, DDDDD: is the only accurate representation of this class/ professor. Hou zooms through the lectures without pausing to see whether we understand or not (which I, even as a math major, often didn't) and if someone asks him a question he acts annoyed. I remember one time he was going over solutions to a practice midterm, and JUST barely finished before class was over. Then, he proceeded to tell us, "Well, I had time to finish all the problems on the practice midterm, so you guys should have time to finish the midterm too." ...Wait, what? No, Zuoliang Hou. No.
Dec 2008 
SO WONDERFUL. She is truly a gem! Take her class! She wants to do everything and anything to make sure that you do well in her class and that you understand the information. Her English isn't perfect, but it's pretty close. As far as math professors go, she's amazing!
May 2008 
Virdol is a mathematician, not a teacher. He is brilliant as the former, dismal as the latter. I love math, but found this class an ordeal of the highest order. He completely failed to cover the basic concepts behind differential equations; rather, he churned through the mechanics of solutions. I found myself having to use MIT's excellent OCW (Open CourseWare) videos of the 2003 lecture series by Professor Arthur Mattuck. I strongly recommend avoiding this professor if possible.
Jan 2008 
Very nice guy; he explains things rather well, and talks TO you, not down to you (he's rather young as well, but he's cool in general). The course is very fair, but a bit easy since. His midterms are very similar to his practice tests, which made the curve a little harsh if you screw up little things too much. Just put in a little bit of effort and be careful of your work as you write it through. ODE is mostly just memorization of methods.
Dec 2007 
Baykur is a nice guy. His problem  he has nothing to contribute that's not from the book. That is, aside from a really good sense of humor and some great oneliners. His examples, his explanations, his proofs etc were all taken straight out of the Boyce and DiPrima ODE book. The homeworks have about 40% of their answers in the Student Solutions Manual or the SSM has a problem that is very close to the one you're solving. The midterms were exactly like the practice midterms. The final was the same. He's a nice guy. Kind of a cute, lovable nerd. The TA's were cool and marginally helpful but all frustratingly put their Office Hours at pretty much the same time.
Dec 2007 
Im taking this class as a Pass/Fail so i dont really care about my grades so this review may be biased. I think he's really quite bad as a teacher. You dont understand what hes saying sometimes and you just go in and copy the stuff he writes on the board.ive really learnt nothing much, and the little part that i do, i gain it from doing the homework That said, he tries to be reasonable and he knows when students are facing difficulties i.e when hwk is too much or finals clash with other subjects. He is quite accomodating when it comes to this Quite a couple of students score well too, so i guess this should be considered an ok class(personally i found it hard but i guess if you just memorize his midterm practices it should be ok). But if you want to learn,forget taking him
Aug 2007 
Gallagher is a brilliant, eloquent & likeable professor who spends his classes weaving through proofs; his approach to teaching is very theoryoriented. Unfortunately, not all those attempts ended satisfactorily, and we often had classes that ended abruptly or were left incomplete. The text book was easy enough to understand though. That said, he was teaching the Engineering version of ODE, and did occasionally make a concerted effort to include examples & solve text book problems. The material was best learnt in classes where he did this. My biggest qualm with Gallagher were his tests though. The two midterms were unbelievably easy, completely distorting the curve, so that a 96% ended up being a B. His final was a Multiple Choice+ No partial credit & he made it difficult to make up for the midterms. Worst of all, his grading system averages the letter grades you received in the HW, midterms & final (double counted). In short: Brilliant, quirky & eloquent professor; loves the theory & neglects the administrative/practical side of the class.
Jun 2007 
Brilliant mathematician but terrible professor. I only went to class 5 times and 2 of them were to take midterms. The few classes I did attend were confusing as he does not explain each step clearly and just makes big jumps in the examples he writes on the board without explaining the necessary logic in figuring those steps out. That said, the course is moderately difficult but with a friend and the solution guide the problem sets are manageable. I learned this subject completely from the book and with the practice midterms and final he posts a couple classes before I got an A in the class. The practice tests are very similar to the actual tests so learn those cold and you should be fine for the test.
Apr 2007 
I cannot understand the good reviews that have been written about this guy. He is perhaps the worst teacher that i have encountered at Columbia. He might have been good previously, but by now is worthless because he is too old and senile. He writes the intricacies of unimportant proofs on the boards and does most of his work with colored crayons, which is extremely frustrating for those students who do not bring such an array of colors to class. He also created the easiest exam i have seen, which made the curve extraordinarily high. if you got one mistake you dropped a letter grade. Finally, in his class there were probably 3 or 4 examples of blatant cheating (talking, passing blue books, having an open text at their feet) that I observed during the first midterm. When he was confronted with this problem by a student he did nothing but shrug and stutter. Do not take a class from this man. He should retire.
Jan 2007 
He is an alright guy but not the most talented of professors. You will pretty much be teaching yourself all the material.
Jan 2007 
Prof. Sirbu was a great man and good teacher but the material was rather difficult to learn in depth in the little time available. The material isn't hard to learn, the problem is the amount of concepts that need to be learned each week. I actually did every homework and got a 10/10 on almost every single one, I even did the questions that weren't assigned, I thought I was on top of the material but somehow got a below average grade on midterm and final. The curve was pretty harsh. I had never received less than a B in any math class but ended up with a C in this one :(
Jan 2007 
Virdol is new to Columbia and still learning the ropes of how things work. He is a fairly decent instructor but the homeworks can be very long. We had a very small class in the fall so grading was tough. Its pretty standard with 2 midterms and a final. ODE is a drag and you need to do the problems on your own so going to class isn't all that helpful. He is fairly accesible and posts problems that are the same on both the 7th and 8th editions of the textbook (so you can save money buying the earlier edition)
Jan 2007 
I've never had a problem in the math dept. and Prof. Sirbu is no exception. He's very approachable and wasn't condescending. He will stray from necessary topics in class every once in a while, but he tells you what you need to know for the exams. He's average, but only in the best way.
Mar 2006 
There were two ODE classes, one taught by professor Paul and another by another teacher. The other teacher had his class full to capacity (110 students). Professor Paul had literally 15 students in the Math 314 room (large lecture hall). If this wasn't enough to give a general picture, his lectures are not understandable to someone with a regular understanding of mathematics. While I can see his love for math and the topic, I did not share it and this class is reccommended only if you like the more theory and proof part of mathematics. He focuses too much on proofs, rather than hard problems with answers. His homework is erratically assigned and involved 20  40 problems which honestly takes a minimum of 6 hours to complete. However, he gives only a few thus it makes up for it. His homework assignments however, do teach you what you need to know and attending lectures is not neccessary (asside from finding out class bulletins as he does not use Courseworks). One thing is, I believe he tries very hard for his students, though does not realize half of them don't understand anything and he has a love for mathematics that only a few could appreciate.
Jan 2006 
Overall Mihai is a good teacher. He's not spectacular but you learn the material well enough. He's pretty straight forward. I found it easier to pay attention to him than to read the book (book explanations are too long). It's true, you'll get bored listening to him but if you pay attention you'll pretty much learn whatever it is you need to do well on his tests. Always do the practice final exams and his practice problems to guarantee and A in his class. I think he's improved a lot in his teaching. I think the bad reviews are from people who doze off in class (which is semi easy to do unfortunately).
Dec 2005 
What a nice man. Professor Sirbu is thorough, moves at a reasonable pace, and explains concepts VERY clearly. If a concept is not clear, just ask him during class. Sometimes his inclass responses are limited (his classes are fairly content dense) but he is always willing to spend as much time as necessary during office hours to make sure you understand everything. Sirbu is very professional, so don't expect too many jokes during class. But, office hours reveal that he does have a sense of humor. Professors in the Math department tend to suck, but this man is very very good. Highly recommended for ODE. His Romanian accent is kind of funny. One downside, for some reason he loves greek symbols and uses them whenever he can. He used symbols I'd never seen before (one that literally looks like a squiggle!!!) Take ODE with this man, you'll like it!
May 2005 
very knowledgeable TA, i frequent his morning office hours  has an understandable way to solve every problem, and would even lead me into solving a problem if i had difficulty rather than only telling me the approach. the best part of it is he speaks english.
Jan 2005 
Professor Sirbu is a very good teacher. He is bright and excellently prepared for class. His lecures are clear and move at a leisurely but steady pace, covering significant ground over the course of the semester: first order equations, existence and uniqueness theory, general theory of homogeneous and nonhomogenoues higher order equations, systems of linear equations, stability analysis of nonlinear systems, Laplace transform methods for initial value problems, and series solutions. This corresponds to chapters 1  7 and 9 from the course textbook "Elementary Differential Equations" by Boyce and DiPrima, which is good but not very advanced. In addition, Professor Sirbu gave a few lectures on interesting or more advanced topics, such as Liapunov functions or Distribution theory, which were not examined. He has a noticable Romanian accent, but his English is excellent and in no way impedes his teaching. The level of rigor is that of an intermediate level course for mathematicians or students of similar mathematical maturity. No knowledge of real analysis, such as is required for the proof of the general existence and uniqueness theorems, is presumed; however, multivariable calculus and linear algebra at both a conceptual and calculatory level are necessary. In addition, the ability to read and write proofs is very beneficial; especially the problem sets tend to contain at least one proof. From an academic and didactic point of view this course more than fulfilled my expectations. It has to be noted that while this is and introductory and not entirely rigorous treatement of Ordinary Differential Equations, this is a course for mathematicians. Although the results and techniques of the course can be applied to a myriad of problems, the course does not focus on applications or spend a lot of time with examples. This is also reflected in Sirbu's teaching style: he tends to cover the general theory before working some simple examples. The homework assignements were fairly easy (ca. 12 hours a week) and mainly reinforce concepts from the lecture. Although the grading was fair, the TAs were somtimes careless in their marking and provided no comments whatsoever when points were taken off. The first midterm, although not hard, was definitely too long for the alotted time; the last question was dropped retroactively. The second midterm was a good deal easier. While the TAs grade the straighforward calculatory midterm problems, Professor Sirbu marked the more involved problems himself to ensure fair grading. Before the final, he held a 2 hour long review session, and  at the bidding of a student  made up a full practice final. The final istelf, although cummulative, was neither long nor exceptionally challenging. It contained 1 proof and was marked entirely by the Professor. Regarding overall grading Professor Sirbu is  like another reviewer mentioned  on the generous side of fair. Finally, Sirbu is extremely nice and very approachable. Whether after class, during office hours, or via email, he is always happy to go over or even beyond any part of the material. In general a very good professor. If you get a chance, take a class with him. Do not expect anything spectacular, but very thorough and professional teaching.
Jan 2005 
The way Mihai teaches ODE is that he treats it not as a topic of its own, but only a tool for other subjects. In other words, he breezes through the material as if it were merely a refresher or a review. It is hard work to keep up with him in class, and to stay awake until the end. I disagree with any reviews that cite his (evident but comprehensible) Romanian accent as the cause for his tedious lectures. As boring as his lectures may be, I would suggest that students attend class anyways. Mihai does well in using intuition to teach  a sign of his sharpness and thorough understanding of the material. You could rely only on the textbook, but some concepts are better explained by Prof. Sirbu. Don't be afraid to ask him to write more darkly on the chalkboard!!! As far as his grading goes, he is on the generous side of fair, at least on all exams. The class HW average may have been a 7 out of 10, but I'd blame the students' carelessness, not Mihai's harsh grading. I'd take another class with him, if only he would differentiate the cream of the crop from the very good by awarding A+'s...
Dec 2004 
Sirbu's lectures are hard to follow and, like others say, it's very easy for the students to just zone out completely. That is not his fault entirely ,though, since english is not his native language. Problems sets are hard and are graded rather harshly(average 7 out of 10 for the class). Other than that, Sirbu gives good review problems for the exams and is fairly easy on the grading. Also, I like how he always pass back previous problem sets and exam at the next class. (That is if you bother going to lecture at all to pick them up.) So if you don't have other professors for ODE (yes, don't take Mao Pei), take him and you'll be ok.
Dec 2004 
The reason this guy does not have a lot of ratings is that he is an average professor. He covers a lot of material (more than average). He grades fairly. The curve is pretty good. His teaching can get a little fast but if you ask him to slow down he will slow down and explain more clearly. He is incredibly helpful at office hours and gives great review problems from the book before exams. I'd say definitely take a class with him but it's not like he is one of those that you MUST take
Dec 2004 
Professor Sirbu is pretty straightforward about teaching. If you can pay attention during the class, he covers everything pretty well. It's easy to zone out trying to follow him though, especially during a long derivation; I found I had to keep reminding myself of what the point was during proofs and such. He's nice about questions though, and he'll explain things if they don't make sense.
Aug 2004 
I can see where people say that he's a pretty cool guy. He's definitely trying to put a hipster spin on mathematicians with his tongue ring and laid back attitude. That's all well and good, but he's an uptight son of a bitch. He really hates it when students disrupt his lectures. He doesn't have patience with students who struggle on some concepts. If anything, what I took from ODE was what I learned from the book, not what he taught. Always disorganized, his idea of an example is so basic the book doesn't bother with it. It makes homework all the more difficult since he chooses problems that include stuff we've never learned. He's an arrogant mathematician who's got a serious Napolean complex.
May 2004 
Not too bad. Easier than the other ODE classes. Pretty nice guy. Very straightforward, as his example problems look very similar to test and quiz questions.
Nov 2003 
Prof. Paul is a very good teacher who honestly wants his students to fall in love with the beauty of math, and he makes every effort to do this in lectures. But I had to drop this class after the midterm because the exam was so heavily based on the theory and proofs he was covering in class and not on the techniques we learned through the problem sets. He demands so much of his students and brings up so many difficult ideas that it drives many people away from the area; I'm no longer pursuing a math concentration because the material in this class was so over my head, and it was supposed to be a relatively easy course. Sean Paul is a great guy for math majors, but be prepared to not just understand the techniques but also be able to utilize the theories in unexpected ways. Considering the material covered, I was suprised at how little I understood what was being taught at lectures.
Nov 2003 
Please do not take this class if you intend to have a life beyond mathematics. I don't consider myself a math genius, but I've done fairly well in my previous classes in this class I wanted to sit down and cry. The first midterm was impossible (I dropped the class after that) and had nothing to do with the homeworks that take an impossible amount of time to complete.
Feb 2003 
Aww, he is SUCH a sweetie! His quizzes and tests are straightforward... maybe TOO easy in light of the breadth and complexity of the textbook. In class, he explains with lucidity and a sprinkling of humor. Warning: His accent is a thick, authentic Russian, but after a few weeks you stop noticing it. Heck, the only thing that distracted me was my latent attraction to this kind, earnest, and brilliant little man.
Apr 2002 
igor's ok. Like, at first i thought he sucked, but like he seems to grow on you. If you dont sit in the first few rows, the quasirussian he speaks can be incomprehensible. He's pretty straight out of the book. if you do the work and keep up, you should be good.
Apr 2002 
Professor Krichever speaks english moderately well  you'll be fine as long as you sit within the first 5 or so rows. if you don't sit up close, you won't be able to hear him, much less understand him. Krichever is an adequate teacher, but is far from spectacular. Bottom line, if you're willing to put in the work, you will learn ODE, but if you're like most Columbia students and are looking for an easy way out, this isn't it.
Dec 2001 
Professor Gallagher is an excellent professor. He has extremely clear lectures and is always willing to work with people outside of class.
Apr 2001 
He's a boring lecturer, I'll give you that. However, he does make an effort to answer questions in his office hours, and after class. His exams are straightforward, and the homework is short and easy. Do the homework, skip the class, study, and you'll probably get an A if you're smart. If you're not math oriented, stay far away from this class.