src/HOL/Algebras.thy
2010-02-10 haftmann 2010-02-10 moved less_eq, less to Orderings.thy; moved abs, sgn to Groups.thy
2010-02-10 haftmann 2010-02-10 moved constants inverse and divide to Ring.thy
2010-02-05 haftmann 2010-02-05 added explaining comment; added ac_simps slot; drop unused abstract lattice; dropped mysterious syntax declaration
2010-01-28 haftmann 2010-01-28 new theory Algebras.thy for generic algebraic structures