let L be RelStr ; for S being SubRelStr of L
for a, b being Element of
for x, y being Element of st x = a & y = b & x <= y holds
a <= b
let S be SubRelStr of L; for a, b being Element of
for x, y being Element of st x = a & y = b & x <= y holds
a <= b
let a, b be Element of ; for x, y being Element of st x = a & y = b & x <= y holds
a <= b
let x, y be Element of ; ( x = a & y = b & x <= y implies a <= b )
assume A1:
( x = a & y = b )
; ( not x <= y or a <= b )
A2:
the InternalRel of S c= the InternalRel of L
by Def13;
assume
[x,y] in the InternalRel of S
; ORDERS_2:def 9 a <= b
hence
[a,b] in the InternalRel of L
by A1, A2; ORDERS_2:def 9 verum