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Questions that are about research in mathematics, or about the job of a research mathematician, without being mathematical problems or statements in the strictest sense. Do not use this tag for easy or supposedly easy mathematical questions.

1 vote
0 answers
268 views

Recreating the wheel [closed]

I recently finished my Phd in pure maths and I am looking for open problems in my research area, functional analysis. Without going into the details, I stumbled onto an interesting problem and I shar …
Mustafa Said's user avatar
  • 3,699
106 votes
12 answers
21k views

What is entropy, really?

I first saw the term "entropy" in a chemistry course while studying thermodynamics. During my graduate studies I encountered the term in many different areas of mathematics. Can anyone explain why thi …
4 votes

Real analysis has no applications?

I have a good undergraduate analysis book, "Real Analysis with Real Applications," by Kenneth R. Davidson and Allan P. Donsig. The book is divided into two parts. Part A deals with "Abstract Analysi …
15 votes

Examples of great mathematical writing

Riemann's paper, "On the number of primes less than a given magnitude," is the reason why I decided to study mathematics (at the graduate level and beyond). I read the paper as an undergraduate and …
1 vote

Understanding/Mastering Analysis in Topology, necessary?

I was working with some fellow grad students (studying algebraic topology) a few years ago and they were having trouble computing some integrals. This was not unusual, but then they asked me if one e …
Mustafa Said's user avatar
  • 3,699
6 votes

Interesting Calculus Questions/Exercises

The following problem is often found in introductory Real Analysis courses but can be solved by IVT: Let $f :[0,1] \to [0,1]$ be continuous. Show that f(x) has a fixed point. In other words, there …
6 votes

What are your favorite instructional counterexamples?

My favorite counter-example is given in the short paper, "Almost Commuting Unitaries," by R. Exel and T. Loring. Here is a little background. Two $n \times n$ matrices $A$ and $B$ are said to be "alm …
1 vote

What are your favorite instructional counterexamples?

Another one of my favorite counter examples is $2\mathbb{Z}$ which is a RNG, or a ring without identity.
0 votes

Nontrivial question about Fibonacci numbers?

Ask them to prove that the ratios of the Fibonacci sequence tends to the golden ratio. That is $\frac{F_n}{F_{n-1}} \to \phi$. This can be done with basic calculus.