let M be non empty MetrSpace; :: thesis: for P, Q being non empty Subset of (TopSpaceMetr M) st P is compact & Q is compact holds
min_dist_max P,Q >= 0
let P, Q be non empty Subset of (TopSpaceMetr M); :: thesis: ( P is compact & Q is compact implies min_dist_max P,Q >= 0 )
assume
( P is compact & Q is compact )
; :: thesis: min_dist_max P,Q >= 0
then consider x1, x2 being Point of M such that
A1:
( x1 in P & x2 in Q & dist x1,x2 = min_dist_max P,Q )
by WEIERSTR:37;
thus
min_dist_max P,Q >= 0
by A1, METRIC_1:5; :: thesis: verum