// The simple curve singularity An for n odd and all non-free // indecomposable MCM modules LIB "conn.lib"; int n = 101; int p = (n+1)/2; ring s = (0,I), (x,y), dp; minpoly = I2+1; ideal i = x2+y^(n+1); qring a = std(i); int l; list MCM; for (l=1;l<=p-1;l++) { matrix M[2][2] = x, y^(n-l+1), y^l, -x; MCM[l] = M; } matrix N1[1][1] = x + I*y^p; matrix N2[1][1] = x - I*y^p; MCM[p] = N1; MCM[p+1] = N2; list sMCM = MCM; sMCM[p] = N2; sMCM[p+1] = N1; print("Curve An for n odd:"); print("-------"); int i; for(i=1;i<=size(MCM);i++) { print("Module:"); print("-------"); print(MCM[i]); print("-------"); print("Obstructions:"); print("-------"); print(KSKernel(MCM[i])); print(LClass(MCM[i])); print("-------"); }