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D.6.13.18 T_12

Procedure from library sing.lib (see sing_lib).

Usage:
T_12(i[,any]); i = ideal

Return:
T_12(i): list of 2 modules:
* standard basis of T_1-module =T_1(i), 1st order deformations
* standard basis of T_2-module =T_2(i), obstructions of R=P/i
If a second argument is present (of any type) return a list of 9 modules, matrices, integers:
[1]= standard basis of T_1-module
[2]= standard basis of T_2-module
[3]= vdim of T_1
[4]= vdim of T_2
[5]= matrix, whose cols present infinitesimal deformations
[6]= matrix, whose cols are generators of relations of i(=syz(i))
[7]= matrix, presenting Hom_P(syz/kos,R), lifted to P
[8]= presentation of T_1-module, no std basis
[9]= presentation of T_2-module, no std basis

Display:
k-dimension of T_1 and T_2 if printlevel >= 0 (default)

Note:
Use proc miniversal from deform.lib to get miniversal deformation of i, the list contains all objects used by proc miniversal.

Example:
 


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            User manual for Singular version 3-1-6, Dec 2012, generated by texi2html.