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D.6.13.17 T_2
Procedure from library sing.lib (see sing_lib).
- Usage:
- T_2(id[,<any>]); id = ideal
- Return:
- T_2(id): T_2-module of id . This is a std basis of a presentation of
the module of obstructions of R=P/id, if P is the basering.
If a second argument is present (of any type) return a list of
4 modules and 1 ideal:
[1]= T_2(id)
[2]= standard basis of id (ideal)
[3]= module of relations of id (=1st syzygy module of id)
[4]= presentation of syz/kos
[5]= relations of Hom_P([3]/kos,R), lifted to P
The list contains all non-easy objects which must be computed
to get T_2(id).
- Display:
- k-dimension of T_2(id) if printlevel >= 0 (default)
- Note:
- The most important information is probably vdim(T_2(id)).
Use proc miniversal to get equations of the miniversal deformation.
Example:
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