src/HOL/Relation.thy
author oheimb
Thu Jan 08 17:56:32 1998 +0100 (1998-01-08)
changeset 4528 ff22e16c5f2f
parent 3499 ce1664057431
child 4746 a5dcd7e4a37d
permissions -rw-r--r--
added Univalent
     1 (*  Title:      Relation.thy
     2     ID:         $Id$
     3     Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
     4     Copyright   1996  University of Cambridge
     5 *)
     6 
     7 Relation = Prod +
     8 consts
     9     id          :: "('a * 'a)set"               (*the identity relation*)
    10     O           :: "[('b * 'c)set, ('a * 'b)set] => ('a * 'c)set" (infixr 60)
    11     inverse    :: "('a*'b) set => ('b*'a) set"     ("(_^-1)" [1000] 999)
    12     "^^"        :: "[('a*'b) set,'a set] => 'b set" (infixl 90)
    13     Domain      :: "('a*'b) set => 'a set"
    14     Range       :: "('a*'b) set => 'b set"
    15     trans       :: "('a * 'a)set => bool"       (*transitivity predicate*)
    16     Univalent   :: "('a * 'b)set => bool"
    17 defs
    18     id_def        "id == {p. ? x. p = (x,x)}"
    19     comp_def      "r O s == {(x,z). ? y. (x,y):s & (y,z):r}"
    20     inverse_def   "r^-1 == {(y,x). (x,y):r}"
    21     Domain_def    "Domain(r) == {x. ? y. (x,y):r}"
    22     Range_def     "Range(r) == Domain(r^-1)"
    23     Image_def     "r ^^ s == {y. ? x:s. (x,y):r}"
    24     trans_def     "trans(r) == (!x y z. (x,y):r --> (y,z):r --> (x,z):r)"
    25     Univalent_def "Univalent r == !x y. (x,y):r --> (!z. (x,z):r --> y=z)"
    26 end