src/HOL/AxClasses/Tutorial/MonoidGroupInsts.thy
author nipkow
Mon Oct 21 09:50:50 1996 +0200 (1996-10-21)
changeset 2115 9709f9188549
parent 1247 18b1441fb603
permissions -rw-r--r--
Added trans_tac (see Provers/nat_transitive.ML)
     1 (*  Title:      HOL/AxClass/Tutorial/MonoidGroupInsts.thy
     2     ID:         $Id$
     3     Author:     Markus Wenzel, TU Muenchen
     4 
     5 Add derived class inclusions monoid < semigroup and group < monoid to
     6 type signature -- some kind of 'abstract instantiations'.
     7 *)
     8 
     9 MonoidGroupInsts = Monoid + Group +
    10 
    11 (* monoids are semigroups *)
    12 
    13 instance
    14   monoid < semigroup            (Monoid.assoc)
    15 
    16 
    17 (* groups are monoids *)
    18 
    19 instance
    20   group < monoid                (assoc, left_unit, right_unit)
    21 
    22 end