set R = {[{} ,{} ]};
reconsider R = {[{} ,{} ]} as Relation ;
A1: field R =
{{} ,{} }
by RELAT_1:32
.=
{{} }
by ENUMSET1:69
;
take
R
; :: thesis: ( R is reflexive & R is antisymmetric & R is (F2) & R is (C1) )
thus
R is reflexive
:: thesis: ( R is antisymmetric & R is (F2) & R is (C1) )
thus
R is antisymmetric
:: thesis: ( R is (F2) & R is (C1) )
thus
R is (F2)
:: thesis: R is (C1) proof
let x,
y,
z be
set ;
:: according to RELAT_2:def 8,
RELAT_2:def 16 :: thesis: ( not x in field R or not y in field R or not z in field R or not [x,y] in R or not [y,z] in R or [x,z] in R )
assume
(
x in field R &
y in field R &
z in field R &
[x,y] in R &
[y,z] in R )
;
:: thesis: [x,z] in R
then
(
x = {} &
z = {} )
by A1, TARSKI:def 1;
hence
[x,z] in R
by TARSKI:def 1;
:: thesis: verum
end;
thus
R is (C1)
; :: thesis: verum