|  |  7.3.14 modulo (plural) 
See also
 syz (plural).Syntax:modulo (ideal_expression,ideal_expression)
 modulo (module_expression,module_expression)Type:module
Purpose:modulo(h1,h2)represents , where  and  are considered as submodules of the same free module  (l=1 for ideals). Let
  (resp.  ) be the matrix of size  (resp.  ), having the
generators of  (resp.  )as columns. Then
  , where  is the induced map given by  . 
 modulo(h1,h2)returns generators of
the kernel of this induced map.
Note: If, for at least one of or  ,the attribute isHomogis st, thenmodulo(h1,h2)also sets this attribute (if the weights are compatible).
Example:|  | LIB "ncalg.lib";
def A = makeUsl2();
setring A; // this algebra is U(sl_2)
option(redSB);
option(redTail);
ideal H2 = e2,f2,h2-1;
H2 = twostd(H2);
print(matrix(H2)); // print H2 in a compact form
==> h2-1,fh-f,eh+e,f2,2ef-h-1,e2
ideal H1 = std(e);
ideal T = modulo(H1,H2);
T = NF(std(H2+T),H2);
T = std(T);
T;
==> T[1]=h-1
==> T[2]=e
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