let M be PseudoMetricSpace; for V, Q being Element of M -neighbour ex v being Real st V,Q is_dst v
let V, Q be Element of M -neighbour ; ex v being Real st V,Q is_dst v
consider p being Element of M such that
A1:
V = p -neighbour
by Th15;
consider q being Element of M such that
A2:
Q = q -neighbour
by Th15;
A3:
q in Q
by A2, Th4;
p in V
by A1, Th4;
then
V,Q is_dst dist (p,q)
by A3, Th21;
hence
ex v being Real st V,Q is_dst v
; verum