  Let $X,Y$ be topological vector spaces or metric spaces, and let {$f:X\times
Y \to \Re $} be a real function lower semicontinuous in the first variable and
upper semicontinuous in the second one. It is proved that $f$ is globally
measurable. Sierpinski (1925) has been raised this question in the case
$X=Y=\Re $. This particular case was solved by Kempisty (1929). The actual
result has applications in Calculus of Variations.
