Frobby Version 0.9.0 Available

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Bjarke Hammersholt Roune

Sep 23, 2011, 4:42:46 PM9/23/11
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*** Version 0.9.0, 2011-09-23

The main new features are support for Euler characteristic computation
and improvements to the Hilbert-Poincare series functionality.

- Added support for computing Euler characteristic
- Added a deformation algorithm for computing Hilbert-Poincare series
- Added the Bigatti et al. algorithm for computing Hilbert-Poincare
- Improved the Slice algorithm implementation for computing H-P
- All option names can now be given as a unique prefix just as for
action names
- The analyze action can now report on strong and weak genericity
- The library interface now supports primary decomposition
- The library interface now supports associated primes
- Reading input monomial ideals is now significantly faster

The new Euler characteristic code uses a new algorithm that is joint
work with Eduardo Saenz-de-Cabezon. As documented in our paper, the
Frobby implementation of this algorithm is much faster than
implementations of Euler characteristic algorithms in other
systems. The euler action has many options, but the default should be
fastest for nearly all ideals.

The Hilbert-Poincare series code was written to compare the Slice
algorithm, the deformation algorithm and the Bigatti et
al. algorithm. The deformation has as far as I know never previously
been implemented or even very explicitly described in the
litterature. The Bigatti algorithm wasn't faster initially after
implementing it as described in the litterature, but with some
additional improvements it got significantly better. It still is not
faster for all ideals, but the improved version is still usually the
best algorithm which is why it is the default algorithm used.
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