M=[1,2;0,3];
[N,d]=coff(M)
N/d
inv(%s*eye()-M)
//NNNNNNNNNNNNNNNNN NNNNNNNNNNNNNNNNNNNNNNNNNN
//coff .. resolvent (cofactor method)
//Calling Sequence
//[N,d]=coff(M [,var])
//Arguments
//M square real matrix
// var character string
//N polynomial matrix (same size as M)
//d polynomial (characteristic polynomial poly(A,'s'))
//Description
//coff computes R=(s*eye()-M)^-1 for M a real matrix. R is given by N/d.
//N = numerator polynomial matrix.
//d = common denominator.
//var character string ('s' if omitted)