Pfaffian Systems of A-Hypergeometric Equations I: Bases of Twisted Cohomology Groups

Takayuki Hibi, Kenta Nishiyama, Nobuki Takayama

This is the third revision. We study bases of Pfaffian systems for $A$-hypergeometric system. Gröbner deformations give bases. These bases also give those for twisted cohomology gr…