Singular

LIB "gradedModules.lib";
ring r;
module R=grobj(module([x,y,z]),intvec(0:3));
grview(R);
==> Graded homomorphism: r^3 <- r(-1), given by a matrix, with degrees: 
==>     .1 ...
==>     -- +..
==>  0 : 1 |.1
==>  0 : 1 |.2
==>  0 : 1 |.3
==>     ==    
==>      1    
module S=grobj(module([x,0,y],[xy,zy+x2,0]),intvec(0:3));
grview(S);
==> Graded homomorphism: r^3 <- r(-1) + r(-2), given by a matrix, with degree\
   s: 
==>      ..1 ..2 ....
==>      --- --- +...
==>   0 :  1   2 |..1
==>   0 :  -   2 |..2
==>   0 :  1   - |..3
==>      === ===     
==>        1   2     
def Q=grconcat(R,S);
grview(Q);
==> Graded homomorphism: r^3 <- r(-1)^2 + r(-2), given by a square matrix, wi\
   th degrees: 
==>      ..1 ..2 ..3 ....
==>      --- --- --- +...
==>   0 :  1   1   2 |..1
==>   0 :  1   -   2 |..2
==>   0 :  1   1   - |..3
==>      === === ===     
==>        1   1   2