de.rwth.domains
Interface PreLowerSemiLattice

All Superinterfaces:

POSet, Set

All Known Subinterfaces:

CompleteLattice, Lattice, LowerSemiLattice, PreLattice

public interface PreLowerSemiLattice

extends POSet

Interface for pre lower semi lattices. Pre lower semi lattices are partially ordered sets, where the greatest lower bound might not exist for two elements.

Version:

$Id: PreLowerSemiLattice.java,v 1.2 2002/09/17 06:53:53 mohnen Exp $

Author:

Markus Mohnen

Inner classes inherited from class de.rwth.domains.Set

Set.Default

Method Summary

java.lang.Object

meet(java.lang.Object e1, java.lang.Object e2) Computes the greatest lower bound of two elements if it exists.

Methods inherited from interface de.rwth.domains.POSet

le, lt

Methods inherited from interface de.rwth.domains.Set

equals, isElement, iterator, iteratorSkel, size, sizeSkel

Method Detail

meet

public java.lang.Object meet(java.lang.Object e1,
                             java.lang.Object e2)

Computes the greatest lower bound of two elements if it exists.
Implementations should guarantee that meet is commutative and associative. Furthermore, meet(e1,e2)=e1 iff le(e1,e2). If one of the arguments is null, the result must be null as well.

Parameters:

e1 - a value of type Object

e2 - a value of type Object

Returns:

the greatest lower bound of e1 and e2 or null if this does not exists

See Also:

Domain.checkProperties(PreLowerSemiLattice lsl)