theorem Th45: :: MESFUN12:45

for X1, X2 being non empty set
for f being PartFunc of [:X1,X2:],ExtREAL
for x being Element of X1 holds
( ProjPMap1 ((max+ f),x) = max+ (ProjPMap1 (f,x)) & ProjPMap1 ((max- f),x) = max- (ProjPMap1 (f,x)) )