TopStruct(# the carrier of (TOP-REAL n),the topology of (TOP-REAL n) #) = TopSpaceMetr (Euclid n)
by EUCLID:def 8;
then reconsider A' = A, B' = B as Subset of ;
take
min_dist_min A',B'
; ex A', B' being Subset of st
( A = A' & B = B' & min_dist_min A',B' = min_dist_min A',B' )
take
A'
; ex B' being Subset of st
( A = A' & B = B' & min_dist_min A',B' = min_dist_min A',B' )
take
B'
; ( A = A' & B = B' & min_dist_min A',B' = min_dist_min A',B' )
thus
( A = A' & B = B' & min_dist_min A',B' = min_dist_min A',B' )
; verum