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A.4.5 Deformations
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The libraries
sing.lib , respextively deform.lib , contain
procedures to compute total and base space of the miniversal (= semiuniversal)
deformation of an isolated complete intersection singularity, respectively
of an arbitrary isolated singularity.
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The procedure
deform in sing.lib returns a matrix whose columns
represent all 1st order deformations. More precisely, if
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The procedure
versal in deform.lib computes a formal
miniversal deformation up to a certain order which can be
prescribed by the user. For a complete intersection the 1st order
part is already miniversal.
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The procedure
versal extends the basering to a new ring with
additional deformation parameters which contains the equations for the
miniversal base space and the miniversal total space.
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There are default names for the objects created, but the user may also
choose their own names.
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If the user sets
printlevel=2; before running versal , some
intermediate results are shown. This is useful since versal
is already complicated and might run for some time on more
complicated examples. (type help versal; )
We compute for the same examples as in the section T1 and T2
the miniversal deformations:
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