let X be non empty finite Subset of REAL; for f being Function of [:X,X:],REAL
for z being non empty finite Subset of REAL
for A being real number st z = rng f & A >= max z holds
for x, y being Element of X holds f . (x,y) <= A
let f be Function of [:X,X:],REAL; for z being non empty finite Subset of REAL
for A being real number st z = rng f & A >= max z holds
for x, y being Element of X holds f . (x,y) <= A
let z be non empty finite Subset of REAL; for A being real number st z = rng f & A >= max z holds
for x, y being Element of X holds f . (x,y) <= A
let A be real number ; ( z = rng f & A >= max z implies for x, y being Element of X holds f . (x,y) <= A )
assume that
A1:
z = rng f
and
A2:
A >= max z
; for x, y being Element of X holds f . (x,y) <= A
now let x,
y be
Element of
X;
f . (x,y) <= A
f . [x,y] = f . (
x,
y)
;
then reconsider c =
f . [x,y] as
real number ;
dom f = [:X,X:]
by FUNCT_2:def 1;
then
[x,y] in dom f
by ZFMISC_1:def 2;
then
c in z
by A1, FUNCT_1:def 5;
then
f . (
x,
y)
<= max z
by XXREAL_2:def 8;
hence
f . (
x,
y)
<= A
by A2, XXREAL_0:2;
verum end;
hence
for x, y being Element of X holds f . (x,y) <= A
; verum