codim M
i1 : R = ZZ/101[a..d];
i2 : M = coker matrix{{a,b},{c,d}} o2 = cokernel | a b | | c d | 2 o2 : R-module, quotient of R
i3 : codim M o3 = 1
The returned value is the usual codimension if R is an integral domain or, more generally, equidimensional.