let L be RelStr ; :: thesis: for S being full SubRelStr of L
for a, b being Element of L
for x, y being Element of S st x = a & y = b & a <= b & x in the carrier of S & y in the carrier of S holds
x <= y
let S be full SubRelStr of L; :: thesis: for a, b being Element of L
for x, y being Element of S st x = a & y = b & a <= b & x in the carrier of S & y in the carrier of S holds
x <= y
let a, b be Element of L; :: thesis: for x, y being Element of S st x = a & y = b & a <= b & x in the carrier of S & y in the carrier of S holds
x <= y
let x, y be Element of S; :: thesis: ( x = a & y = b & a <= b & x in the carrier of S & y in the carrier of S implies x <= y )
assume A1: ( x = a & y = b ) ; :: thesis: ( not a <= b or not x in the carrier of S or not y in the carrier of S or x <= y )
A2: the InternalRel of S = the InternalRel of L |_2 the carrier of S by Def14;
assume A3: [a,b] in the InternalRel of L ; :: according to ORDERS_2:def 9 :: thesis: ( not x in the carrier of S or not y in the carrier of S or x <= y )
assume ( x in the carrier of S & y in the carrier of S ) ; :: thesis: x <= y
then [x,y] in [:the carrier of S,the carrier of S:] by ZFMISC_1:106;
hence [x,y] in the InternalRel of S by A1, A2, A3, XBOOLE_0:def 4; :: according to ORDERS_2:def 9 :: thesis: verum