Permanents of incidence matrices
Paul J. Nikolai · Mathematics of Computation · 1960
The analogue of the Laplace expansion is easily shown to remain valid for the permanent, but for computational purposes it is of little help. The calculations described in this paper were made practicable by a computational device given by H. J. Ryser. I shall state Ryser's result, which has heretofore not been published, as a theorem. THEOREM 1. Denote by Ar a matrix obtained from A by replacing r of the column vectors of A by zero vectors. Denote by S(Ar) the product of the row sums of Ar. Then