fact: Definition sesqui := [qualify M : 'M_n | M == ((-1) ^+ eps_theta.1) *: M ^t eps_theta.2].
imports: HB(structures) mathcomp(all_ssreflect ssralg fingroup zmodp poly ssrnum) mathcomp(matrix mxalgebra vector falgebra ssrnum algC algnum) mathcomp(fieldext) mathcomp(vector)