Tuesday, 13 March 2007

co.combinatorics - Generalization of permanent definition based on number of permutation cycles

Let A be an n by n matrix and x a free parameter. Define
p(A,x)=sumpiinSnxn(pi)A1pi(1)ldotsAnpi(n),
where pi ranges over the permutation group Sn and n(pi) is the number of cycles in the cycle decomposition of pi. Clearly, p(A,1)=perm(A), the permanent. In general, p(A,x) has properties in common with the permanent such as p(PAQ,x)=p(A,x) for permutation matrices P,Q.



Is this a well-known structure in combinatorics and where might I find more information?

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