5.1.70 lead

Syntax:

lead ( poly_expression )
lead ( vector_expression )
lead ( ideal_expression )
lead ( module_expression )

Type:

the same as the input type

Purpose:

returns the leading (or initial) term(s) of a polynomial, a vector, resp. of the generators of an ideal or module with respect to the monomial ordering.

Note:

IN may be used instead of lead.

Example:

ring r=32003,(x,y,z),(c,ds); poly f=2x2+3y+4z3; vector v=[2x10,f]; ideal i=f,z; module m=v,[0,0,2+x]; lead(f); ==> 3y lead(v); ==> [2x10] lead(i); ==> _[1]=3y ==> _[2]=z lead(m); ==> _[1]=[2x10] ==> _[2]=[0,0,2] lead(0); ==> 0