15 Answers votes newest views recent 8Real-world applications of mathematics, by arxiv subject area? 5What’s a groupoid? What’s a good example of a groupoid? 3Proving Hodge decomposition without using the theory of elliptic operators? 2Algorithm to Find all the Cycle Bases in a Graph 7Question about Banach’s matchbox problem. 13What are “variational crimes” and who coined the term? 0$\ell^p$ version of singular values 2What are some conserved quantities of Poisson brackets? 2What m minimizes E(|m-X|^3) for a random variable X? 8Example of symplectic and hamiltonian diffeomorphism on $S^2$ and $T^2$ 4integration of a laplacian 1FEM on a Laplacian 0reduced symplectic form 1Construction of finite element differential forms based on deRham sequences 4Is there a categorification of the integers in terms of “graded sets”?