New posts in big-list

Favourite open problem?

successful absurd formalities

What are some examples of hard theorems in category theory?

Tricks for quickly reading off the eigenvalues of a matrix

Examples of sets which are not obviously sets

Preparation for Putnam?

I want to start mathematics from scratch. What should I begin with?

Conjectures Disproven by the use of Computers?

Isoperimetric inequality, isodiametric inequality, hyperplane conjecture... what are the inequalities of this kind known or conjectured?

Easy to understand examples of category theoretic theorems that are useful

Famous uses of the inclusion-exclusion principle?

Non-numerical vector space examples

What are some elementary results (number theory) using theorems that went long-unproven?

Beautiful Mathematical Images [closed]

Examples of $\mathcal{O}_X$-modules that are not quasi-coherent sheaves

The proofs of the fundamental Theorem of Algebra [closed]

Common misconceptions about math

When will a group be Abelian?

Beautiful Theorems and what constitutes as beautiful [closed]

Theorems in the form of "if and only if" such that the proof of one direction is extremely EASY to prove and the other one is extremely HARD [closed]