Metamath Proof Explorer


Theorem ispconn

Description: The property of being a path-connected topological space. (Contributed by Mario Carneiro, 11-Feb-2015)

Ref Expression
Hypothesis ispconn.1
|- X = U. J
Assertion ispconn
|- ( J e. PConn <-> ( J e. Top /\ A. x e. X A. y e. X E. f e. ( II Cn J ) ( ( f ` 0 ) = x /\ ( f ` 1 ) = y ) ) )

Proof

Step Hyp Ref Expression
1 ispconn.1
 |-  X = U. J
2 unieq
 |-  ( j = J -> U. j = U. J )
3 2 1 eqtr4di
 |-  ( j = J -> U. j = X )
4 oveq2
 |-  ( j = J -> ( II Cn j ) = ( II Cn J ) )
5 4 rexeqdv
 |-  ( j = J -> ( E. f e. ( II Cn j ) ( ( f ` 0 ) = x /\ ( f ` 1 ) = y ) <-> E. f e. ( II Cn J ) ( ( f ` 0 ) = x /\ ( f ` 1 ) = y ) ) )
6 3 5 raleqbidv
 |-  ( j = J -> ( A. y e. U. j E. f e. ( II Cn j ) ( ( f ` 0 ) = x /\ ( f ` 1 ) = y ) <-> A. y e. X E. f e. ( II Cn J ) ( ( f ` 0 ) = x /\ ( f ` 1 ) = y ) ) )
7 3 6 raleqbidv
 |-  ( j = J -> ( A. x e. U. j A. y e. U. j E. f e. ( II Cn j ) ( ( f ` 0 ) = x /\ ( f ` 1 ) = y ) <-> A. x e. X A. y e. X E. f e. ( II Cn J ) ( ( f ` 0 ) = x /\ ( f ` 1 ) = y ) ) )
8 df-pconn
 |-  PConn = { j e. Top | A. x e. U. j A. y e. U. j E. f e. ( II Cn j ) ( ( f ` 0 ) = x /\ ( f ` 1 ) = y ) }
9 7 8 elrab2
 |-  ( J e. PConn <-> ( J e. Top /\ A. x e. X A. y e. X E. f e. ( II Cn J ) ( ( f ` 0 ) = x /\ ( f ` 1 ) = y ) ) )