2010-07-12 ago dropped superfluous [code del]s
2010-04-27 ago tuned class linordered_field_inverse_zero
2010-04-26 ago use new classes (linordered_)field_inverse_zero
2010-04-26 ago dropped group_simps, ring_simps, field_eq_simps; classes division_ring_inverse_zero, field_inverse_zero, linordered_field_inverse_zero
2010-04-24 ago Library/Fraction_Field.thy: ordering relations for fractions
2010-04-23 ago separated instantiation of division_by_zero
2010-02-24 ago renamed theory Rational to Rat
2009-07-14 ago code attributes use common underscore convention
2009-06-23 ago Added Library/Fraction_Field.thy: The fraction field of any integral