MathOverflow

Let $\mathcal{M}$ be a smooth manifold and $T \mathcal{M}$ its tangent bundle. A retraction is a smooth map$$R: T \mathcal{M} \rightarrow \mathcal{M}$$such that for each $x \in \mathcal{M}$, denoting by $R_x$ the restriction $R_x=\left.R\right|_{T_x...

While studying Berndt's Ramanujan's Lost Notebook Vol. 2, page 369 (chapter on Springerlink), I found that Ramanujan gave values of a certain expression $$\frac{1}{\sqrt{Q_n}}\left(\sqrt {n} P_n-\frac{6}{\pi}\right)\tag{1}$$ for a few integer values...

An equi-$n$-square is an $n$ by $n$ array of cells filled with the symbols $1,2,\dots,n$ so that each symbol occurs exactly $n$ times.(Every Latin square of order $n$ is an equi-$n$-square, but the converse does not hold.)For $k \le n$, a partial transversal...

Let's consider two non-singular integer matrices $A,B \in\mathbb{Z}^{n\times n}$. I want a test to check if $A\times B^{-1}$ is integral (or no denominators). I am referring to Colton Pauderis and Arne Storjohann's "Deterministic unimodularity certification...