4 problems

Let $a_n,\ldots,a_1$ be a sequence of morphisms represented by a polygon with exactly one boundary whose winding number is $-2$. Fix a morphism $a_n$ in each such sequence, and wri…

Let $(\Sigma,\mathscr{P},\eta_\Gamma)$ be a graded punctured surface with a line field $\eta_\Gamma$ induced by a ribbon graph $\Gamma$, and let $B_\Gamma$ be the associated Brauer…

Let $A$ be a Brauer tree algebra, let $u$ be its associated graded algebra, and let $overline{nu}$ be the algebra considered in the source. Write $Gamma$ for the Auslander–Reiten…

Ramification least-common-multiple conjecture. The least common multiple of the orders of $\sigma_r$ and $\sigma_s$ should have significant meaning in modular representation theory…