let X be non empty set ; for S being SigmaField of X
for A, B being Element of S
for er being ExtReal holds chi (er,A,X) is B -measurable
let S be SigmaField of X; for A, B being Element of S
for er being ExtReal holds chi (er,A,X) is B -measurable
let A, B be Element of S; for er being ExtReal holds chi (er,A,X) is B -measurable
let er be ExtReal; chi (er,A,X) is B -measurable
a1:
Xchi (A,X) is B -measurable
by MEASUR10:32;
a2:
dom (Xchi (A,X)) = X
by FUNCT_2:def 1;