2 problems

Let $K\Delta$ be a PHI algebra derived equivalent to the category of coherent sheaves on a weighted projective line, and let $M$ be its canonical sincere $K\Delta$-module. Here, a…

Let $K\Delta$ be a piecewise hereditary incidence algebra (PHI algebra), and let $HH^1(K\Delta)$ denote its first Hochschild cohomology group. An algebra is simply connected when i…