Step |
Hyp |
Ref |
Expression |
1 |
|
eqvreltr.1 |
|- ( ph -> EqvRel R ) |
2 |
|
eqvrelrel |
|- ( EqvRel R -> Rel R ) |
3 |
1 2
|
syl |
|- ( ph -> Rel R ) |
4 |
|
simpr |
|- ( ( A R B /\ B R C ) -> B R C ) |
5 |
|
brrelex1 |
|- ( ( Rel R /\ B R C ) -> B e. _V ) |
6 |
3 4 5
|
syl2an |
|- ( ( ph /\ ( A R B /\ B R C ) ) -> B e. _V ) |
7 |
|
simpr |
|- ( ( ph /\ ( A R B /\ B R C ) ) -> ( A R B /\ B R C ) ) |
8 |
|
breq2 |
|- ( x = B -> ( A R x <-> A R B ) ) |
9 |
|
breq1 |
|- ( x = B -> ( x R C <-> B R C ) ) |
10 |
8 9
|
anbi12d |
|- ( x = B -> ( ( A R x /\ x R C ) <-> ( A R B /\ B R C ) ) ) |
11 |
6 7 10
|
spcedv |
|- ( ( ph /\ ( A R B /\ B R C ) ) -> E. x ( A R x /\ x R C ) ) |
12 |
|
simpl |
|- ( ( A R B /\ B R C ) -> A R B ) |
13 |
|
brrelex1 |
|- ( ( Rel R /\ A R B ) -> A e. _V ) |
14 |
3 12 13
|
syl2an |
|- ( ( ph /\ ( A R B /\ B R C ) ) -> A e. _V ) |
15 |
|
brrelex2 |
|- ( ( Rel R /\ B R C ) -> C e. _V ) |
16 |
3 4 15
|
syl2an |
|- ( ( ph /\ ( A R B /\ B R C ) ) -> C e. _V ) |
17 |
|
brcog |
|- ( ( A e. _V /\ C e. _V ) -> ( A ( R o. R ) C <-> E. x ( A R x /\ x R C ) ) ) |
18 |
14 16 17
|
syl2anc |
|- ( ( ph /\ ( A R B /\ B R C ) ) -> ( A ( R o. R ) C <-> E. x ( A R x /\ x R C ) ) ) |
19 |
11 18
|
mpbird |
|- ( ( ph /\ ( A R B /\ B R C ) ) -> A ( R o. R ) C ) |
20 |
19
|
ex |
|- ( ph -> ( ( A R B /\ B R C ) -> A ( R o. R ) C ) ) |
21 |
|
dfeqvrel2 |
|- ( EqvRel R <-> ( ( ( _I |` dom R ) C_ R /\ `' R C_ R /\ ( R o. R ) C_ R ) /\ Rel R ) ) |
22 |
21
|
simplbi |
|- ( EqvRel R -> ( ( _I |` dom R ) C_ R /\ `' R C_ R /\ ( R o. R ) C_ R ) ) |
23 |
22
|
simp3d |
|- ( EqvRel R -> ( R o. R ) C_ R ) |
24 |
1 23
|
syl |
|- ( ph -> ( R o. R ) C_ R ) |
25 |
24
|
ssbrd |
|- ( ph -> ( A ( R o. R ) C -> A R C ) ) |
26 |
20 25
|
syld |
|- ( ph -> ( ( A R B /\ B R C ) -> A R C ) ) |