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7.7.20.0. preimageNC
Procedure from library ncpreim.lib (see ncpreim_lib).
- Usage:
- preimageNC(A,f,J[,P,eng]); A ring, f map or ideal, J ideal,
P optional string, eng optional int
- Assume:
- f defines a map from A to the basering.
- Return:
- nothing, instead exports an object `preim' of type ideal to ring A,
being the preimage of J under f.
- Note:
- If P is given and not equal to the empty string, the preimage is
exported to A under the name specified by P.
Otherwise (and by default), P is set to `preim'.
If eng<>0, std is used for Groebner basis computations,
otherwise (and by default) slimgb is used.
If printlevel=1, progress debug messages will be printed,
if printlevel>=2, all the debug messages will be printed.
- Remark:
- Reference: (Lev)
Example:
See also:
preimage (plural).
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