Professor

## Jonathan Rubin

**Most Helpful Review**

Spring 2020 - Professor Rubin is the GOAT. For the first few weeks of class, he was experimenting with the class structure and used surveys for students to voice their opinions. To say the least, he took our responses into account and reduced the amount of worksheets per week and gave us more time for quizzes. He was a super accommodating professor! He had pre-lecture videos, which introduced us to the material and he elaborated on the concepts in class. Professor Rubin was friendly and open to questions in class and during office hours. He also has the best mugs. Overall, I would recommend him and I would definitely take another class with him. The grade breakdown was: Optional Homework (super helpful to do in preparation for quizzes/exams) 20% worksheets (based on completion) 20% Midterms (second one was harder than the first) 40% quizzes (takes 3 questions from the hw so you are guaranteed a 7/10) 20% final

**Most Helpful Review**

Fall 2019 - I think that the quarter that I took it was Professor Rubin’s first quarter teaching, but I would 11/10 recommend him. Lectures/Professor Professor Rubin is extremely clear during lectures and his class was appropriately paced. He will stop to explain and answer students’ questions if there are any. He also has a pretty good sense of humor and I feel like he is funny without really trying, as in he will randomly make some remarks that make the class laugh. Participation/Discussions Discussions are mandatory for the attendance grade and my TA passed around a sign in sheet. For my discussion section, the TA went over the course content briefly and then gave us a worksheet to do. It’s not mandatory to turn the worksheet in, but just good practice. At the end of the last 20 ish minutes, the TA will go over the worksheet. I’m not sure if that’s how all discussion sections go though. Piazza/Extra Help Usually, any hw or content related questions will be answered by the TAs and they are very helpful and respond pretty quickly. Any logistics related questions the professor will also respond pretty quickly. As for office hours, I have personally never went to any, but whenever office hours are cancelled due to a holiday, the professor will offer make up office hours after break. Homework/Exams There is weekly homework, most of which are textbook problems, with the occasional extra problems from the professor. The homework problems are, in my opinion, much harder than his actual exams. It took me quite a bit of time and thinking and looking at Piazza to finish the problems. However, the amount is not crazy a lot and I think it was pretty reasonable for a math class. As mentioned earlier, the exams aren’t that bad and is actually pretty easy if you know the content and have attempted the problems. There is also more than enough time to complete the problems. If I remember correctly, the midterms each have 4 problems (some with multiple parts) and final has 8 problems. The problems aren’t tricky and are really just testing your understanding. Also, both midterms had an average of around 80 or 84, which probably says a lot about the exam difficulty. The only thing, though, is that the professor doesn’t give out practice problems. He will give a study guide but it’s really just a list of topics that he has covered. Overall, I highly Professor Rubin’s class. However, although the exams weren’t hard, I would still recommended studying ahead and doing the hw/practice problems. Discrete math covers a variety of topics so it’s important to be familiar with all of them.

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**Most Helpful Review**

Fall 2020 - Professor Rubin is a great professor. His lectures are clear, but filled with a lot of content. He always pauses for questions and is always willing to help, which I like. Since this is an honors course, we learn about 1.5x the material than regular 115a (Topics we learned that I don't think are covered in 115a: dual spaces, double dual basis, transpose, determinants, Real and Complex Spectral Theorem, Singular Value Decomposition). All his lectures are recorded and he uploads them to CCLE rather fast. Discussions are usually recorded but to be honest, I only attended them two times (I'm so sorry Bar). If you don't have much proof experience, this class will help you transition into proof writing. You'll learn the proof techniques during the first few discussions. Our primary textbook for this class is Linear Algebra by Hoffman and Kunze, but you can find the PDF of it online. You'll need this book because he assigns some homework assignments from this book. This book is a little hard to read, but whether you're taking 115a or 115ah, I would definitely recommend Linear Algebra Done Right by Axler. His grading scheme is as follows (only one grading scheme): 30% Final Exam 15% Midterm 1 15% Midterm 2 20% Quizzes (Lowest quiz dropped; 8 quizzes) 20% Homework (10 HW assignments) Usually every week on Thursday, expect a quiz. These quizzes always stressed me out but it'll help you stay on track. There's a 24 hour window to take the quiz, but after opening the quiz, there's a 30 minute timer to take it and submit it. Each quiz is two problems, usually these are short proofs. Doing the homework assignments is a good way to study. There's a homework due every Thursday at midnight. He uploads the homework assignments in 3 parts, which total to about 8-10 problems a week. Only 3 problems will be graded for corrected, and he'll tell you which problems these are. The rest of the homework is graded on completeness. Try to start them early and don't procrastinate. On average, I would say I spent 3-6 hours a week on homework, but Rubin and the TA are very helpful on Piazza and Office Hours. There are two midterms for this class. I felt the midterms were slightly harder than the homework, but the averages were high. Midterm 1 had an average score of 39.8/50, midterm 2 average was 42.81/50. There are five questions on each midterm and I spent the whole day working on it. FYI: He took nine days to grade midterm 1, and ten days to grade midterm 2, which is pretty fast. After he publishes the exam scores, he also uploads the solutions to CCLE which are very helpful. The final had 10 questions which took me more than 12 hours to complete. The final felt much more challenging than the midterms, so I don't think I did well on it. Rubin cares a lot about his students. At the beginning of every lecture, he conducts a Zoom Poll asking how we're doing. He also sends us several surveys asking us for feedback and our opinions about the class. Do these surveys because he is really dedicated to improving and making the class better for his students. Linear algebra isn't my favorite subject, but I definitely learned a lot in this class. Overall, I would definitely recommend Rubin! Edit: The final has already been graded (only took two days to grade). The mean was 72/100 with standard deviation 17. My calculated grade of 77% turned out to be a C+, so I'm not too sure how generous his curve is.

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**Most Helpful Review**

Spring 2021 - This review is from the perspective of a pure math major. I hold an interest in this class mainly because I believe it helps with understanding graduate-level math. Professor Rubin is a great lecturer, as he did a great job explaining the terms and answering our questions. He is also very helpful in office hours and is easy to approach to. However, I do think the pace of the class is a bit quick since we basically skim through the whole textbook "Category Theory in Context". We didn't have a chance to learn many things in detail, and many useful facts are left out for us to read in our own time. I used a lot of textbooks and notes other than the recommended ones, and they turn out to be helpful for filling in the gaps. Another problem is that the concepts are sometimes way too abstract and it is difficult to figure out everything without having an understanding on them beforehand. It would be helpful if you have experience with graduate-level algebra (i.e. MATH 210A), or have read the Algebra book by Serge Lang since they give you a focus of Category Theory on abstract algebra (groups and rings). Overall, very nice professor, but very hard class (at least for me). Here are the grade components: Homework (75%): weekly assignment containing 6 problems each. Final (25%): take-home exam with a 2-week window to figure everything out.