let X, Y be Subset of REAL; ( ( for r, p being Real st r in X & p in Y holds
r < p ) implies ex g being Real st
for r, p being Real st r in X & p in Y holds
( r <= g & g <= p ) )
assume
for r, p being Real st r in X & p in Y holds
r < p
; ex g being Real st
for r, p being Real st r in X & p in Y holds
( r <= g & g <= p )
then
for r, p being Real st r in X & p in Y holds
r <= p
;
then consider g being Real such that
A1:
for r, p being Real st r in X & p in Y holds
( r <= g & g <= p )
by AXIOMS:1;
reconsider g = g as Real ;
take
g
; for r, p being Real st r in X & p in Y holds
( r <= g & g <= p )
thus
for r, p being Real st r in X & p in Y holds
( r <= g & g <= p )
by A1; verum