let X be non empty set ; for E being Equivalence_Relation of X
for x, y being set
for C being Element of Class E st x in C & y in C holds
[x,y] in E
let E be Equivalence_Relation of X; for x, y being set
for C being Element of Class E st x in C & y in C holds
[x,y] in E
let x, y be set ; for C being Element of Class E st x in C & y in C holds
[x,y] in E
let C be Element of Class E; ( x in C & y in C implies [x,y] in E )
assume A1:
( x in C & y in C )
; [x,y] in E
reconsider EE = E as transitive Tolerance of X ;
consider xe being object such that
A2:
( xe in X & C = Class (E,xe) )
by EQREL_1:def 3;
thus
[x,y] in E
by EQREL_1:22, A1, A2; verum