involut.lib
LIB "involut.lib"; def A = makeUsl(2); setring A; map I = A,-e,-f,-h; //correct antiauto involution isInvolution(I); ==> 1 map J = A,3*e,1/3*f,-h; // antiauto but not involution isInvolution(J); ==> 0 map K = A,f,e,-h; // not antiauto isInvolution(K); ==> 0