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D.6.17.2 invunit
Procedure from library mondromy.lib (see mondromy_lib).
- Usage:
- invunit(u,n); u poly, n int
- Assume:
- The polynomial u is a series unit.
- Return:
- The procedure returns the series inverse of u up to order n
or a zero polynomial if u is no series unit.
- Display:
- The procedure displays comments if printlevel>=1.
Example:
| LIB "mondromy.lib";
ring R=0,(x,y),dp;
invunit(2+x3+xy4,10);
==> 1/8x2y8-1/16x9+1/4x4y4+1/8x6-1/4xy4-1/4x3+1/2
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