let M be Pnet; ( f_prox M c= [:(Elements M),(Elements M):] & f_flow M c= [:(Elements M),(Elements M):] )
A1:
(Flow M) | the carrier of M c= Flow M
by RELAT_1:59;
Flow M c= [:(Elements M),(Elements M):]
by Th8;
then A2:
(Flow M) | the carrier of M c= [:(Elements M),(Elements M):]
by A1, XBOOLE_1:1;
A3:
((Flow M) ~) | the carrier of M c= (Flow M) ~
by RELAT_1:59;
(Flow M) ~ c= [:(Elements M),(Elements M):]
by Th8;
then A4:
((Flow M) ~) | the carrier of M c= [:(Elements M),(Elements M):]
by A3, XBOOLE_1:1;
the carrier of M c= Elements M
by XBOOLE_1:7;
then A5:
[: the carrier of M, the carrier of M:] c= [:(Elements M),(Elements M):]
by ZFMISC_1:96;
id the carrier of M c= [: the carrier of M, the carrier of M:]
by RELSET_1:13;
then A6:
id the carrier of M c= [:(Elements M),(Elements M):]
by A5, XBOOLE_1:1;
((Flow M) | the carrier of M) \/ (((Flow M) ~) | the carrier of M) c= [:(Elements M),(Elements M):]
by A2, A4, XBOOLE_1:8;
hence
f_prox M c= [:(Elements M),(Elements M):]
by A6, XBOOLE_1:8; f_flow M c= [:(Elements M),(Elements M):]
A7:
Flow M c= [:(Elements M),(Elements M):]
by Th8;
id (Elements M) c= [:(Elements M),(Elements M):]
by RELSET_1:13;
hence
f_flow M c= [:(Elements M),(Elements M):]
by A7, XBOOLE_1:8; verum