let R be RelStr ; :: thesis: ( R is asymmetric implies the InternalRel of R misses the InternalRel of R ~ )
assume A1:
R is asymmetric
; :: thesis: the InternalRel of R misses the InternalRel of R ~
assume
the InternalRel of R meets the InternalRel of R ~
; :: thesis: contradiction
then consider x being set such that
A2:
x in the InternalRel of R
and
A3:
x in the InternalRel of R ~
by XBOOLE_0:3;
consider y, z being set such that
A4:
x = [y,z]
by A3, RELAT_1:def 1;
A5:
[z,y] in the InternalRel of R
by A3, A4, RELAT_1:def 7;
the InternalRel of R is asymmetric
by A1, Def5;
then A6:
the InternalRel of R is_asymmetric_in field the InternalRel of R
by RELAT_2:def 13;
( y in field the InternalRel of R & z in field the InternalRel of R )
by A2, A4, RELAT_1:30;
hence
contradiction
by A2, A4, A5, A6, RELAT_2:def 5; :: thesis: verum