P. 49 of Theorem List - Intuitionistic Logic Explorer

Theorem List for Intuitionistic Logic Explorer - 4801-4900   *Has distinct variable group(s)

Type	Label	Description
Statement
Theorem	releq 4801	Equality theorem for the relation predicate. (Contributed by NM, 1-Aug-1994.)
|- ( A = B -> ( Rel A <-> Rel B ) )
Theorem	releqi 4802	Equality inference for the relation predicate. (Contributed by NM, 8-Dec-2006.)
|- A = B   =>    |- ( Rel A <-> Rel B )
Theorem	releqd 4803	Equality deduction for the relation predicate. (Contributed by NM, 8-Mar-2014.)
|- ( ph -> A = B )   =>    |- ( ph -> ( Rel A <-> Rel B ) )
Theorem	nfrel 4804	Bound-variable hypothesis builder for a relation. (Contributed by NM, 31-Jan-2004.) (Revised by Mario Carneiro, 15-Oct-2016.)
|- F/_ x A   =>    |- F/ x Rel A
Theorem	sbcrel 4805	Distribute proper substitution through a relation predicate. (Contributed by Alexander van der Vekens, 23-Jul-2017.)
|- ( A e. V -> ( [. A / x ]. Rel R <-> Rel [_ A / x ]_ R ) )
Theorem	relss 4806	Subclass theorem for relation predicate. Theorem 2 of [Suppes] p. 58. (Contributed by NM, 15-Aug-1994.)
|- ( A C_ B -> ( Rel B -> Rel A ) )
Theorem	ssrel 4807*	A subclass relationship depends only on a relation's ordered pairs. Theorem 3.2(i) of [Monk1] p. 33. (Contributed by NM, 2-Aug-1994.) (Proof shortened by Andrew Salmon, 27-Aug-2011.)
|- ( Rel A -> ( A C_ B <-> A. x A. y ( <. x , y >. e. A -> <. x , y >. e. B ) ) )
Theorem	eqrel 4808*	Extensionality principle for relations. Theorem 3.2(ii) of [Monk1] p. 33. (Contributed by NM, 2-Aug-1994.)
|- ( ( Rel A /\ Rel B ) -> ( A = B <-> A. x A. y ( <. x , y >. e. A <-> <. x , y >. e. B ) ) )
Theorem	ssrel2 4809*	A subclass relationship depends only on a relation's ordered pairs. This version of ssrel 4807 is restricted to the relation's domain. (Contributed by Thierry Arnoux, 25-Jan-2018.)
|- ( R C_ ( A X. B ) -> ( R C_ S <-> A. x e. A A. y e. B ( <. x , y >. e. R -> <. x , y >. e. S ) ) )
Theorem	relssi 4810*	Inference from subclass principle for relations. (Contributed by NM, 31-Mar-1998.)
|- Rel A   &    |- ( <. x , y >. e. A -> <. x , y >. e. B )   =>    |- A C_ B
Theorem	relssdv 4811*	Deduction from subclass principle for relations. (Contributed by NM, 11-Sep-2004.)
|- ( ph -> Rel A )   &    |- ( ph -> ( <. x , y >. e. A -> <. x , y >. e. B ) )   =>    |- ( ph -> A C_ B )
Theorem	eqrelriv 4812*	Inference from extensionality principle for relations. (Contributed by FL, 15-Oct-2012.)
|- ( <. x , y >. e. A <-> <. x , y >. e. B )   =>    |- ( ( Rel A /\ Rel B ) -> A = B )
Theorem	eqrelriiv 4813*	Inference from extensionality principle for relations. (Contributed by NM, 17-Mar-1995.)
|- Rel A   &    |- Rel B   &    |- ( <. x , y >. e. A <-> <. x , y >. e. B )   =>    |- A = B
Theorem	eqbrriv 4814*	Inference from extensionality principle for relations. (Contributed by NM, 12-Dec-2006.)
|- Rel A   &    |- Rel B   &    |- ( x A y <-> x B y )   =>    |- A = B
Theorem	eqrelrdv 4815*	Deduce equality of relations from equivalence of membership. (Contributed by Rodolfo Medina, 10-Oct-2010.)
|- Rel A   &    |- Rel B   &    |- ( ph -> ( <. x , y >. e. A <-> <. x , y >. e. B ) )   =>    |- ( ph -> A = B )
Theorem	eqbrrdv 4816*	Deduction from extensionality principle for relations. (Contributed by Mario Carneiro, 3-Jan-2017.)
|- ( ph -> Rel A )   &    |- ( ph -> Rel B )   &    |- ( ph -> ( x A y <-> x B y ) )   =>    |- ( ph -> A = B )
Theorem	eqbrrdiv 4817*	Deduction from extensionality principle for relations. (Contributed by Rodolfo Medina, 10-Oct-2010.)
|- Rel A   &    |- Rel B   &    |- ( ph -> ( x A y <-> x B y ) )   =>    |- ( ph -> A = B )
Theorem	eqrelrdv2 4818*	A version of eqrelrdv 4815. (Contributed by Rodolfo Medina, 10-Oct-2010.)
|- ( ph -> ( <. x , y >. e. A <-> <. x , y >. e. B ) )   =>    |- ( ( ( Rel A /\ Rel B ) /\ ph ) -> A = B )
Theorem	ssrelrel 4819*	A subclass relationship determined by ordered triples. Use relrelss 5255 to express the antecedent in terms of the relation predicate. (Contributed by NM, 17-Dec-2008.) (Proof shortened by Andrew Salmon, 27-Aug-2011.)
|- ( A C_ ( ( _V X. _V ) X. _V ) -> ( A C_ B <-> A. x A. y A. z ( <. <. x , y >. , z >. e. A -> <. <. x , y >. , z >. e. B ) ) )
Theorem	eqrelrel 4820*	Extensionality principle for ordered triples, analogous to eqrel 4808. Use relrelss 5255 to express the antecedent in terms of the relation predicate. (Contributed by NM, 17-Dec-2008.)
|- ( ( A u. B ) C_ ( ( _V X. _V ) X. _V ) -> ( A = B <-> A. x A. y A. z ( <. <. x , y >. , z >. e. A <-> <. <. x , y >. , z >. e. B ) ) )
Theorem	elrel 4821*	A member of a relation is an ordered pair. (Contributed by NM, 17-Sep-2006.)
|- ( ( Rel R /\ A e. R ) -> E. x E. y A = <. x , y >. )
Theorem	relsng 4822	A singleton is a relation iff it is an ordered pair. (Contributed by NM, 24-Sep-2013.) (Revised by BJ, 12-Feb-2022.)
|- ( A e. V -> ( Rel { A } <-> A e. ( _V X. _V ) ) )
Theorem	relsnopg 4823	A singleton of an ordered pair is a relation. (Contributed by NM, 17-May-1998.) (Revised by BJ, 12-Feb-2022.)
|- ( ( A e. V /\ B e. W ) -> Rel { <. A , B >. } )
Theorem	relsn 4824	A singleton is a relation iff it is an ordered pair. (Contributed by NM, 24-Sep-2013.)
|- A e. _V   =>    |- ( Rel { A } <-> A e. ( _V X. _V ) )
Theorem	relsnop 4825	A singleton of an ordered pair is a relation. (Contributed by NM, 17-May-1998.) (Revised by Mario Carneiro, 26-Apr-2015.)
|- A e. _V   &    |- B e. _V   =>    |- Rel { <. A , B >. }
Theorem	xpss12 4826	Subset theorem for cross product. Generalization of Theorem 101 of [Suppes] p. 52. (Contributed by NM, 26-Aug-1995.) (Proof shortened by Andrew Salmon, 27-Aug-2011.)
|- ( ( A C_ B /\ C C_ D ) -> ( A X. C ) C_ ( B X. D ) )
Theorem	xpss 4827	A cross product is included in the ordered pair universe. Exercise 3 of [TakeutiZaring] p. 25. (Contributed by NM, 2-Aug-1994.)
|- ( A X. B ) C_ ( _V X. _V )
Theorem	relxp 4828	A cross product is a relation. Theorem 3.13(i) of [Monk1] p. 37. (Contributed by NM, 2-Aug-1994.)
|- Rel ( A X. B )
Theorem	xpss1 4829	Subset relation for cross product. (Contributed by Jeff Hankins, 30-Aug-2009.)
|- ( A C_ B -> ( A X. C ) C_ ( B X. C ) )
Theorem	xpss2 4830	Subset relation for cross product. (Contributed by Jeff Hankins, 30-Aug-2009.)
|- ( A C_ B -> ( C X. A ) C_ ( C X. B ) )
Theorem	xpsspw 4831	A cross product is included in the power of the power of the union of its arguments. (Contributed by NM, 13-Sep-2006.)
|- ( A X. B ) C_ ~P ~P ( A u. B )
Theorem	unixpss 4832	The double class union of a cross product is included in the union of its arguments. (Contributed by NM, 16-Sep-2006.)
|- U. U. ( A X. B ) C_ ( A u. B )
Theorem	xpexg 4833	The cross product of two sets is a set. Proposition 6.2 of [TakeutiZaring] p. 23. (Contributed by NM, 14-Aug-1994.)
|- ( ( A e. V /\ B e. W ) -> ( A X. B ) e. _V )
Theorem	xpex 4834	The cross product of two sets is a set. Proposition 6.2 of [TakeutiZaring] p. 23. (Contributed by NM, 14-Aug-1994.)
|- A e. _V   &    |- B e. _V   =>    |- ( A X. B ) e. _V
Theorem	sqxpexg 4835	The Cartesian square of a set is a set. (Contributed by AV, 13-Jan-2020.)
|- ( A e. V -> ( A X. A ) e. _V )
Theorem	relun 4836	The union of two relations is a relation. Compare Exercise 5 of [TakeutiZaring] p. 25. (Contributed by NM, 12-Aug-1994.)
|- ( Rel ( A u. B ) <-> ( Rel A /\ Rel B ) )
Theorem	relin1 4837	The intersection with a relation is a relation. (Contributed by NM, 16-Aug-1994.)
|- ( Rel A -> Rel ( A i^i B ) )
Theorem	relin2 4838	The intersection with a relation is a relation. (Contributed by NM, 17-Jan-2006.)
|- ( Rel B -> Rel ( A i^i B ) )
Theorem	reldif 4839	A difference cutting down a relation is a relation. (Contributed by NM, 31-Mar-1998.)
|- ( Rel A -> Rel ( A \ B ) )
Theorem	reliun 4840	An indexed union is a relation iff each member of its indexed family is a relation. (Contributed by NM, 19-Dec-2008.)
|- ( Rel U_ x e. A B <-> A. x e. A Rel B )
Theorem	reliin 4841	An indexed intersection is a relation if at least one of the member of the indexed family is a relation. (Contributed by NM, 8-Mar-2014.)
|- ( E. x e. A Rel B -> Rel |^|_ x e. A B )
Theorem	reluni 4842*	The union of a class is a relation iff any member is a relation. Exercise 6 of [TakeutiZaring] p. 25 and its converse. (Contributed by NM, 13-Aug-2004.)
|- ( Rel U. A <-> A. x e. A Rel x )
Theorem	relint 4843*	The intersection of a class is a relation if at least one member is a relation. (Contributed by NM, 8-Mar-2014.)
|- ( E. x e. A Rel x -> Rel |^| A )
Theorem	rel0 4844	The empty set is a relation. (Contributed by NM, 26-Apr-1998.)
|- Rel (/)
Theorem	relopabiv 4845*	A class of ordered pairs is a relation. For a version without a disjoint variable condition, see relopabi 4847. (Contributed by BJ, 22-Jul-2023.)
|- A = { <. x , y >. | ph }   =>    |- Rel A
Theorem	relopabv 4846*	A class of ordered pairs is a relation. For a version without a disjoint variable condition, see relopab 4848. (Contributed by SN, 8-Sep-2024.)
|- Rel { <. x , y >. | ph }
Theorem	relopabi 4847	A class of ordered pairs is a relation. (Contributed by Mario Carneiro, 21-Dec-2013.)
|- A = { <. x , y >. | ph }   =>    |- Rel A
Theorem	relopab 4848	A class of ordered pairs is a relation. (Contributed by NM, 8-Mar-1995.) (Unnecessary distinct variable restrictions were removed by Alan Sare, 9-Jul-2013.) (Proof shortened by Mario Carneiro, 21-Dec-2013.)
|- Rel { <. x , y >. | ph }
Theorem	brabv 4849	If two classes are in a relationship given by an ordered-pair class abstraction, the classes are sets. (Contributed by Alexander van der Vekens, 5-Nov-2017.)
|- ( X { <. x , y >. | ph } Y -> ( X e. _V /\ Y e. _V ) )
Theorem	mptrel 4850	The maps-to notation always describes a relationship. (Contributed by Scott Fenton, 16-Apr-2012.)
|- Rel ( x e. A |-> B )
Theorem	reli 4851	The identity relation is a relation. Part of Exercise 4.12(p) of [Mendelson] p. 235. (Contributed by NM, 26-Apr-1998.) (Revised by Mario Carneiro, 21-Dec-2013.)
|- Rel _I
Theorem	rele 4852	The membership relation is a relation. (Contributed by NM, 26-Apr-1998.) (Revised by Mario Carneiro, 21-Dec-2013.)
|- Rel _E
Theorem	opabid2 4853*	A relation expressed as an ordered pair abstraction. (Contributed by NM, 11-Dec-2006.)
|- ( Rel A -> { <. x , y >. | <. x , y >. e. A } = A )
Theorem	inopab 4854*	Intersection of two ordered pair class abstractions. (Contributed by NM, 30-Sep-2002.)
|- ( { <. x , y >. | ph } i^i { <. x , y >. | ps } ) = { <. x , y >. | ( ph /\ ps ) }
Theorem	difopab 4855*	The difference of two ordered-pair abstractions. (Contributed by Stefan O'Rear, 17-Jan-2015.)
|- ( { <. x , y >. | ph } \ { <. x , y >. | ps } ) = { <. x , y >. | ( ph /\ -. ps ) }
Theorem	inxp 4856	The intersection of two cross products. Exercise 9 of [TakeutiZaring] p. 25. (Contributed by NM, 3-Aug-1994.) (Proof shortened by Andrew Salmon, 27-Aug-2011.)
|- ( ( A X. B ) i^i ( C X. D ) ) = ( ( A i^i C ) X. ( B i^i D ) )
Theorem	xpindi 4857	Distributive law for cross product over intersection. Theorem 102 of [Suppes] p. 52. (Contributed by NM, 26-Sep-2004.)
|- ( A X. ( B i^i C ) ) = ( ( A X. B ) i^i ( A X. C ) )
Theorem	xpindir 4858	Distributive law for cross product over intersection. Similar to Theorem 102 of [Suppes] p. 52. (Contributed by NM, 26-Sep-2004.)
|- ( ( A i^i B ) X. C ) = ( ( A X. C ) i^i ( B X. C ) )
Theorem	xpiindim 4859*	Distributive law for cross product over indexed intersection. (Contributed by Jim Kingdon, 7-Dec-2018.)
|- ( E. y y e. A -> ( C X. |^|_ x e. A B ) = |^|_ x e. A ( C X. B ) )
Theorem	xpriindim 4860*	Distributive law for cross product over relativized indexed intersection. (Contributed by Jim Kingdon, 7-Dec-2018.)
|- ( E. y y e. A -> ( C X. ( D i^i |^|_ x e. A B ) ) = ( ( C X. D ) i^i |^|_ x e. A ( C X. B ) ) )
Theorem	eliunxp 4861*	Membership in a union of cross products. Analogue of elxp 4736 for nonconstant B ( x ). (Contributed by Mario Carneiro, 29-Dec-2014.)
|- ( C e. U_ x e. A ( { x } X. B ) <-> E. x E. y ( C = <. x , y >. /\ ( x e. A /\ y e. B ) ) )
Theorem	opeliunxp2 4862*	Membership in a union of cross products. (Contributed by Mario Carneiro, 14-Feb-2015.)
|- ( x = C -> B = E )   =>    |- ( <. C , D >. e. U_ x e. A ( { x } X. B ) <-> ( C e. A /\ D e. E ) )
Theorem	raliunxp 4863*	Write a double restricted quantification as one universal quantifier. In this version of ralxp 4865, B ( y ) is not assumed to be constant. (Contributed by Mario Carneiro, 29-Dec-2014.)
|- ( x = <. y , z >. -> ( ph <-> ps ) )   =>    |- ( A. x e. U_ y e. A ( { y } X. B ) ph <-> A. y e. A A. z e. B ps )
Theorem	rexiunxp 4864*	Write a double restricted quantification as one universal quantifier. In this version of rexxp 4866, B ( y ) is not assumed to be constant. (Contributed by Mario Carneiro, 14-Feb-2015.)
|- ( x = <. y , z >. -> ( ph <-> ps ) )   =>    |- ( E. x e. U_ y e. A ( { y } X. B ) ph <-> E. y e. A E. z e. B ps )
Theorem	ralxp 4865*	Universal quantification restricted to a cross product is equivalent to a double restricted quantification. The hypothesis specifies an implicit substitution. (Contributed by NM, 7-Feb-2004.) (Revised by Mario Carneiro, 29-Dec-2014.)
|- ( x = <. y , z >. -> ( ph <-> ps ) )   =>    |- ( A. x e. ( A X. B ) ph <-> A. y e. A A. z e. B ps )
Theorem	rexxp 4866*	Existential quantification restricted to a cross product is equivalent to a double restricted quantification. (Contributed by NM, 11-Nov-1995.) (Revised by Mario Carneiro, 14-Feb-2015.)
|- ( x = <. y , z >. -> ( ph <-> ps ) )   =>    |- ( E. x e. ( A X. B ) ph <-> E. y e. A E. z e. B ps )
Theorem	djussxp 4867*	Disjoint union is a subset of a cross product. (Contributed by Stefan O'Rear, 21-Nov-2014.)
|- U_ x e. A ( { x } X. B ) C_ ( A X. _V )
Theorem	ralxpf 4868*	Version of ralxp 4865 with bound-variable hypotheses. (Contributed by NM, 18-Aug-2006.) (Revised by Mario Carneiro, 15-Oct-2016.)
|- F/ y ph   &    |- F/ z ph   &    |- F/ x ps   &    |- ( x = <. y , z >. -> ( ph <-> ps ) )   =>    |- ( A. x e. ( A X. B ) ph <-> A. y e. A A. z e. B ps )
Theorem	rexxpf 4869*	Version of rexxp 4866 with bound-variable hypotheses. (Contributed by NM, 19-Dec-2008.) (Revised by Mario Carneiro, 15-Oct-2016.)
|- F/ y ph   &    |- F/ z ph   &    |- F/ x ps   &    |- ( x = <. y , z >. -> ( ph <-> ps ) )   =>    |- ( E. x e. ( A X. B ) ph <-> E. y e. A E. z e. B ps )
Theorem	iunxpf 4870*	Indexed union on a cross product is equals a double indexed union. The hypothesis specifies an implicit substitution. (Contributed by NM, 19-Dec-2008.)
|- F/_ y C   &    |- F/_ z C   &    |- F/_ x D   &    |- ( x = <. y , z >. -> C = D )   =>    |- U_ x e. ( A X. B ) C = U_ y e. A U_ z e. B D
Theorem	opabbi2dv 4871*	Deduce equality of a relation and an ordered-pair class builder. Compare abbi2dv 2348. (Contributed by NM, 24-Feb-2014.)
|- Rel A   &    |- ( ph -> ( <. x , y >. e. A <-> ps ) )   =>    |- ( ph -> A = { <. x , y >. | ps } )
Theorem	relop 4872*	A necessary and sufficient condition for a Kuratowski ordered pair to be a relation. (Contributed by NM, 3-Jun-2008.) (Avoid depending on this detail.)
|- A e. _V   &    |- B e. _V   =>    |- ( Rel <. A , B >. <-> E. x E. y ( A = { x } /\ B = { x , y } ) )
Theorem	ideqg 4873	For sets, the identity relation is the same as equality. (Contributed by NM, 30-Apr-2004.) (Proof shortened by Andrew Salmon, 27-Aug-2011.)
|- ( B e. V -> ( A _I B <-> A = B ) )
Theorem	ideq 4874	For sets, the identity relation is the same as equality. (Contributed by NM, 13-Aug-1995.)
|- B e. _V   =>    |- ( A _I B <-> A = B )
Theorem	ididg 4875	A set is identical to itself. (Contributed by NM, 28-May-2008.) (Proof shortened by Andrew Salmon, 27-Aug-2011.)
|- ( A e. V -> A _I A )
Theorem	issetid 4876	Two ways of expressing set existence. (Contributed by NM, 16-Feb-2008.) (Proof shortened by Andrew Salmon, 27-Aug-2011.) (Revised by Mario Carneiro, 26-Apr-2015.)
|- ( A e. _V <-> A _I A )
Theorem	coss1 4877	Subclass theorem for composition. (Contributed by FL, 30-Dec-2010.)
|- ( A C_ B -> ( A o. C ) C_ ( B o. C ) )
Theorem	coss2 4878	Subclass theorem for composition. (Contributed by NM, 5-Apr-2013.)
|- ( A C_ B -> ( C o. A ) C_ ( C o. B ) )
Theorem	coeq1 4879	Equality theorem for composition of two classes. (Contributed by NM, 3-Jan-1997.)
|- ( A = B -> ( A o. C ) = ( B o. C ) )
Theorem	coeq2 4880	Equality theorem for composition of two classes. (Contributed by NM, 3-Jan-1997.)
|- ( A = B -> ( C o. A ) = ( C o. B ) )
Theorem	coeq1i 4881	Equality inference for composition of two classes. (Contributed by NM, 16-Nov-2000.)
|- A = B   =>    |- ( A o. C ) = ( B o. C )
Theorem	coeq2i 4882	Equality inference for composition of two classes. (Contributed by NM, 16-Nov-2000.)
|- A = B   =>    |- ( C o. A ) = ( C o. B )
Theorem	coeq1d 4883	Equality deduction for composition of two classes. (Contributed by NM, 16-Nov-2000.)
|- ( ph -> A = B )   =>    |- ( ph -> ( A o. C ) = ( B o. C ) )
Theorem	coeq2d 4884	Equality deduction for composition of two classes. (Contributed by NM, 16-Nov-2000.)
|- ( ph -> A = B )   =>    |- ( ph -> ( C o. A ) = ( C o. B ) )
Theorem	coeq12i 4885	Equality inference for composition of two classes. (Contributed by FL, 7-Jun-2012.)
|- A = B   &    |- C = D   =>    |- ( A o. C ) = ( B o. D )
Theorem	coeq12d 4886	Equality deduction for composition of two classes. (Contributed by FL, 7-Jun-2012.)
|- ( ph -> A = B )   &    |- ( ph -> C = D )   =>    |- ( ph -> ( A o. C ) = ( B o. D ) )
Theorem	nfco 4887	Bound-variable hypothesis builder for function value. (Contributed by NM, 1-Sep-1999.)
|- F/_ x A   &    |- F/_ x B   =>    |- F/_ x ( A o. B )
Theorem	elco 4888*	Elements of a composed relation. (Contributed by BJ, 10-Jul-2022.)
|- ( A e. ( R o. S ) <-> E. x E. y E. z ( A = <. x , z >. /\ ( x S y /\ y R z ) ) )
Theorem	brcog 4889*	Ordered pair membership in a composition. (Contributed by NM, 24-Feb-2015.)
|- ( ( A e. V /\ B e. W ) -> ( A ( C o. D ) B <-> E. x ( A D x /\ x C B ) ) )
Theorem	opelco2g 4890*	Ordered pair membership in a composition. (Contributed by NM, 27-Jan-1997.) (Revised by Mario Carneiro, 24-Feb-2015.)
|- ( ( A e. V /\ B e. W ) -> ( <. A , B >. e. ( C o. D ) <-> E. x ( <. A , x >. e. D /\ <. x , B >. e. C ) ) )
Theorem	brcogw 4891	Ordered pair membership in a composition. (Contributed by Thierry Arnoux, 14-Jan-2018.)
|- ( ( ( A e. V /\ B e. W /\ X e. Z ) /\ ( A D X /\ X C B ) ) -> A ( C o. D ) B )
Theorem	eqbrrdva 4892*	Deduction from extensionality principle for relations, given an equivalence only on the relation's domain and range. (Contributed by Thierry Arnoux, 28-Nov-2017.)
|- ( ph -> A C_ ( C X. D ) )   &    |- ( ph -> B C_ ( C X. D ) )   &    |- ( ( ph /\ x e. C /\ y e. D ) -> ( x A y <-> x B y ) )   =>    |- ( ph -> A = B )
Theorem	brco 4893*	Binary relation on a composition. (Contributed by NM, 21-Sep-2004.) (Revised by Mario Carneiro, 24-Feb-2015.)
|- A e. _V   &    |- B e. _V   =>    |- ( A ( C o. D ) B <-> E. x ( A D x /\ x C B ) )
Theorem	opelco 4894*	Ordered pair membership in a composition. (Contributed by NM, 27-Dec-1996.) (Revised by Mario Carneiro, 24-Feb-2015.)
|- A e. _V   &    |- B e. _V   =>    |- ( <. A , B >. e. ( C o. D ) <-> E. x ( A D x /\ x C B ) )
Theorem	cnvss 4895	Subset theorem for converse. (Contributed by NM, 22-Mar-1998.)
|- ( A C_ B -> `' A C_ `' B )
Theorem	cnveq 4896	Equality theorem for converse. (Contributed by NM, 13-Aug-1995.)
|- ( A = B -> `' A = `' B )
Theorem	cnveqi 4897	Equality inference for converse. (Contributed by NM, 23-Dec-2008.)
|- A = B   =>    |- `' A = `' B
Theorem	cnveqd 4898	Equality deduction for converse. (Contributed by NM, 6-Dec-2013.)
|- ( ph -> A = B )   =>    |- ( ph -> `' A = `' B )
Theorem	elcnv 4899*	Membership in a converse. Equation 5 of [Suppes] p. 62. (Contributed by NM, 24-Mar-1998.)
|- ( A e. `' R <-> E. x E. y ( A = <. x , y >. /\ y R x ) )
Theorem	elcnv2 4900*	Membership in a converse. Equation 5 of [Suppes] p. 62. (Contributed by NM, 11-Aug-2004.)
|- ( A e. `' R <-> E. x E. y ( A = <. x , y >. /\ <. y , x >. e. R ) )