User Dirk

117 votes

What are your favorite instructional counterexamples?

answered Sep 29, 2010 at 23:50

99 votes

Mathematical games interesting to both you and a 5+-year-old child

answered Sep 19, 2017 at 10:27

93 votes

Proofs that require fundamentally new ways of thinking

answered Dec 13, 2010 at 19:08

58 votes

Accepted

Why are optimization problems often called "programs"?

answered Oct 17, 2013 at 13:22

53 votes

What do you do when you're stuck?

answered Feb 6, 2023 at 10:37

50 votes

Changes forced by the pandemic

answered May 28, 2021 at 9:29

40 votes

A sudden smiley? :-)

answered Nov 1, 2012 at 7:42

39 votes

Which way for reading the proofs?

answered Mar 24, 2015 at 9:10

35 votes

Titles composed entirely of math symbols

answered Jul 11, 2011 at 7:19

35 votes

Modeling in pure math

answered Dec 16, 2019 at 5:35

30 votes

Accepted

Most general definition of differentiation

answered Dec 4, 2019 at 11:33

25 votes

Accepted

In search of an early picture of Max Dehn

answered Jun 1, 2012 at 8:42

25 votes

Applications of microlocal analysis?

answered Jan 4, 2017 at 16:20

24 votes

Elementary + short + useful

answered Apr 3, 2011 at 19:06

21 votes

How to generalize the various vector calculus theorems to distributions?

answered May 6, 2021 at 9:09

20 votes

Applications of mathematics

answered Feb 25, 2011 at 9:13

19 votes

Examples of famous 'workhorse' theorems

answered Jul 24, 2014 at 18:24

19 votes

Why do we have two theorems when one implies the other?

answered Jul 12, 2021 at 5:23

18 votes

Notions of convergence not corresponding to topologies

answered Nov 13, 2013 at 11:07

16 votes

What's a great christmas present for someone with a PhD in Mathematics?

answered Dec 13, 2020 at 10:42

15 votes

Examples of common false beliefs in mathematics

answered May 6, 2015 at 8:24

14 votes

"Paradoxes" in $\mathbb{R}^n$

answered Mar 10, 2014 at 10:16

14 votes

Refereeing a Paper

answered Sep 29, 2010 at 23:17

13 votes

When does symmetry in an optimization problem imply that all variables are equal at optimality?

answered Mar 17, 2011 at 8:03

13 votes

Math videos containing real time rough thinking

answered Nov 17, 2021 at 14:31

13 votes

Which theorems have Pythagoras' Theorem as a special case?

answered May 5, 2022 at 12:37

12 votes

Origin of the term "sinc" function

answered Sep 12, 2019 at 21:41

12 votes

Accepted

Convexity and Lipschitz continuity

answered Oct 24, 2020 at 10:44

11 votes

Is the boundary $\partial S$ analogous to a derivative?

answered Nov 17, 2010 at 19:04

11 votes

New grand projects in contemporary math

answered Jan 2, 2013 at 14:16

Stack Exchange Network

245 Answers

What are your favorite instructional counterexamples?

Mathematical games interesting to both you and a 5+-year-old child

Proofs that require fundamentally new ways of thinking

Why are optimization problems often called "programs"?

What do you do when you're stuck?

Changes forced by the pandemic

A sudden smiley? :-)

Which way for reading the proofs?

Titles composed entirely of math symbols

Modeling in pure math

Most general definition of differentiation

In search of an early picture of Max Dehn

Applications of microlocal analysis?

Elementary + short + useful

How to generalize the various vector calculus theorems to distributions?

Applications of mathematics

Examples of famous 'workhorse' theorems

Why do we have two theorems when one implies the other?

Notions of convergence not corresponding to topologies

What's a great christmas present for someone with a PhD in Mathematics?

Examples of common false beliefs in mathematics

"Paradoxes" in $\mathbb{R}^n$

Refereeing a Paper

When does symmetry in an optimization problem imply that all variables are equal at optimality?

Math videos containing real time rough thinking

Which theorems have Pythagoras' Theorem as a special case?

Origin of the term "sinc" function

Convexity and Lipschitz continuity

Is the boundary $\partial S$ analogous to a derivative?

New grand projects in contemporary math