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7.3.1 betti (plural)

Syntax:
betti ( list_expression )
betti ( resolution_expression )
betti ( list_expression , int_expression )
betti ( resolution_expression , int_expression )
Type:
intmat
Note:
in the non-commutative case, computing Betti numbers makes sense only if the basering has homogeneous relations. The output of the command can be pretty-printed using print( , "betti"), i.e., with "betti" as second argument; see below example.
Purpose:
with 1 argument: computes the graded Betti numbers of a minimal resolution of
The argument is considered to be the result of a mres or nres command. This implies that a zero is only allowed (and counted) as a generator in the first module.
For the computation betti uses only the initial monomials. This could lead to confusing results for a non-homogeneous input.

If the optional second argument is non-zero, the Betti numbers will be minimized.

Example:
 


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