let T be non empty TopSpace; for r being Real
for m being Function of [:the carrier of T,the carrier of T:],REAL st r > 0 & m is_metric_of the carrier of T holds
min r,m is_metric_of the carrier of T
let r be Real; for m being Function of [:the carrier of T,the carrier of T:],REAL st r > 0 & m is_metric_of the carrier of T holds
min r,m is_metric_of the carrier of T
let m be Function of [:the carrier of T,the carrier of T:],REAL ; ( r > 0 & m is_metric_of the carrier of T implies min r,m is_metric_of the carrier of T )
assume that
A1:
r > 0
and
A2:
m is_metric_of the carrier of T
; min r,m is_metric_of the carrier of T
let a, b, c be Element of T; PCOMPS_1:def 7 ( ( not (min r,m) . a,b = 0 or a = b ) & ( not a = b or (min r,m) . a,b = 0 ) & (min r,m) . a,b = (min r,m) . b,a & (min r,m) . a,c <= ((min r,m) . a,b) + ((min r,m) . b,c) )
for a, b, c being Element of T holds
( m . a,a = 0 & m . a,b = m . b,a & m . a,c <= (m . a,b) + (m . b,c) )
by A2, PCOMPS_1:def 7;
then
m is_a_pseudometric_of the carrier of T
by Lm8;
then A3:
min r,m is_a_pseudometric_of the carrier of T
by A1, Th30;
( (min r,m) . a,b = 0 implies a = b )
hence
( (min r,m) . a,b = 0 iff a = b )
by A3, Lm8; ( (min r,m) . a,b = (min r,m) . b,a & (min r,m) . a,c <= ((min r,m) . a,b) + ((min r,m) . b,c) )
thus
( (min r,m) . a,b = (min r,m) . b,a & (min r,m) . a,c <= ((min r,m) . a,b) + ((min r,m) . b,c) )
by A3, Lm8; verum