[Haskell-cafe] ANN: signed-multiset-0.1

[Stefan Holdermans]

I am pleased to announce the first release of signed-multiset, which implements an abstract datatype for multisets with negative membership.

The package can be obtained from

  http://hackage.haskell.org/package/signed-multiset-0.1

As always, feedback is welcome.

Cheers,

  Stefan


signed-multiset-0.1
-------------------

Multisets (or bags) are sets in which elements may occur more than once.
The number of times an element occurs in a multiset is called its
multiplicity.

This package provides an efficient implementation of so-called
signed multisets, which generalise multisets by allowing for
negative membership.
That is, elements in a signed multiset can have negative multiplicities.

See also: Wayne D. Blizard. Negative membership.
Notre Dame Journal of Formal Logic/, 31(3):346--368, 1990.