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D.4.6.5 compose
Procedure from library decomp.lib (see decomp_lib).
- Usage:
- compose(f1,...,fn); f1,...,fn poly
compose(I); I ideal,
- Assume:
- the ideal consists of n=ncols(I) >= 1 entries,
where I[1],...,I[n-1] are univariate in the same variable
but I[n] may be multivariate.
- Return:
- poly, the composition I[1](I[2](...I[n]))
- Note:
- this procedure is the inverse of decompose
- See:
- decompose
Example:
| | LIB "decomp.lib";
ring r = 0,(x,y),dp;
compose(x3+1,x2,y3+x);
==> y18+6xy15+15x2y12+20x3y9+15x4y6+6x5y3+x6+1
// or the input as one ideal
compose(ideal(x3+1,x2,x3+y));
==> x18+6x15y+15x12y2+20x9y3+15x6y4+6x3y5+y6+1
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