let X be set ; :: thesis: ( ( for x being set st x in X holds
x is Function ) & X is c=-linear implies ( union X is Relation-like & union X is Function-like ) )
assume that
A1:
for x being set st x in X holds
x is Function
and
A2:
X is c=-linear
; :: thesis: ( union X is Relation-like & union X is Function-like )
thus
for a being set st a in union X holds
ex b, c being set st [b,c] = a
:: according to RELAT_1:def 1 :: thesis: union X is Function-like
let a be set ; :: according to FUNCT_1:def 1 :: thesis: for b1, b2 being set holds
( not [a,b1] in union X or not [a,b2] in union X or b1 = b2 )
let b, c be set ; :: thesis: ( not [a,b] in union X or not [a,c] in union X or b = c )
assume A4:
( [a,b] in union X & [a,c] in union X )
; :: thesis: b = c
then consider x being set such that
A5:
( [a,b] in x & x in X )
by TARSKI:def 4;
consider y being set such that
A6:
( [a,c] in y & y in X )
by A4, TARSKI:def 4;
reconsider x = x as Function by A1, A5;
reconsider y = y as Function by A1, A6;
x,y are_c=-comparable
by A2, A5, A6, ORDINAL1:def 9;
then
( x c= y or y c= x )
by XBOOLE_0:def 9;
hence
b = c
by A5, A6, FUNCT_1:def 1; :: thesis: verum