let S be 1-sorted ; for N being NetStr of S
for M being SubNetStr of N
for x, y being Element of
for i, j being Element of st x = i & y = j & i <= j holds
x <= y
let N be NetStr of S; for M being SubNetStr of N
for x, y being Element of
for i, j being Element of st x = i & y = j & i <= j holds
x <= y
let M be SubNetStr of N; for x, y being Element of
for i, j being Element of st x = i & y = j & i <= j holds
x <= y
let x, y be Element of ; for i, j being Element of st x = i & y = j & i <= j holds
x <= y
let i, j be Element of ; ( x = i & y = j & i <= j implies x <= y )
assume that
A1:
( x = i & y = j )
and
A2:
i <= j
; x <= y
reconsider M = M as SubRelStr of N by Def8;
reconsider i' = i, j' = j as Element of ;
i' <= j'
by A2;
hence
x <= y
by A1, YELLOW_0:60; verum