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5.1.46 homog

Syntax:

homog ( ideal_expression )
homog ( module_expression )

Type:

int

Purpose:

tests for homogeneity: returns 1 for homogeneous input, 0 otherwise.

Syntax:

homog ( polynomial_expression, ring_variable )
homog ( vector_expression, ring_variable )
homog ( ideal_expression, ring_variable )
homog ( module_expression, ring_variable )

Type:

same as first argument

Purpose:

homogenizes polynomials, vectors, ideals, or modules by multiplying each monomial with a suitable power of the given ring variable (which must have weight 1).

Example:
 
  ring r=32003,(x,y,z),ds;
  poly s1=x3y2+x5y+3y9;
  poly s2=x2y2z2+3z8;
  poly s3=5x4y2+4xy5+2x2y2z3+y7+11x10;
  ideal i=s1,s2,s3;
  homog(s2,z);
→ x2y2z4+3z8
  homog(i,z);
→ _[1]=3y9+x5yz3+x3y2z4
→ _[2]=x2y2z4+3z8
→ _[3]=11x10+y7z3+5x4y2z4+4xy5z4+2x2y2z6
  homog(i);
→ 0
  homog(homog(i,z));
→ 1

See ideal; module; poly; vector.


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