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7.5.21.0. isInS
Procedure from library olga.lib (see olga_lib).
- Usage:
- isInS(p, locType, locData(, override)), poly p, int locType,
list/vector/intvec locData(, int override)
- Purpose:
- determine if a polynomial is in a denominator set
- Assume:
- Return:
- int
- Note:
- - returns 0 or 1, depending whether p is in the denominator set
specified by locType and locData
- if override is set, will not normalize locData (use with care)
Example:
| | LIB "olga.lib";
ring R = 0,(x,y,Dx,Dy),dp;
def S = Weyl();
setring S; S;
==> // coefficients: QQ
==> // number of vars : 4
==> // block 1 : ordering dp
==> // : names x y Dx Dy
==> // block 2 : ordering C
==> // noncommutative relations:
==> // Dxx=x*Dx+1
==> // Dyy=y*Dy+1
// monoidal localization
poly g1 = x^2*y+x+2;
poly g2 = y^3+x*y;
list L = g1,g2;
poly g = g1^2*g2;
poly f = g-1;
isInS(g, 0, L); // g is in the denominator set
==> 1
isInS(f, 0, L); // f is NOT in the denominator set
==> 0
// geometric localization
ideal p = x-1, y-3;
g = x^2+y-3;
f = (x-1)*g;
isInS(g, 1, p); // g is in the denominator set
==> 1
isInS(f, 1, p); // f is NOT in the denominator set
==> 0
// rational localization
intvec v = 2;
g = y^5+17*y^2-4;
f = x*y;
isInS(g, 2, v); // g is in the denominator set
==> 1
isInS(f, 2, v); // f is NOT in the denominator set
==> 0
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