L = ring M
This command returns the ring over which the NCMatrix is defined.
i1 : A = QQ{a,b,c,d} o1 = A o1 : NCPolynomialRing
i2 : M = ncMatrix {{a,b,c,d},{b,c,d,a}} o2 = | a b c d | | b c d a | o2 : NCMatrix
i3 : ring M o3 = A o3 : NCPolynomialRing