P. 367 of Theorem List - Metamath Proof Explorer

Theorem List for Metamath Proof Explorer - 36601-36700   *Has distinct variable group(s)

Type	Label	Description
Statement
Definition	df-cup 36601	Define the little cup function. See brcup 36671 for its value. (Contributed by Scott Fenton, 14-Apr-2014.)
⊢ Cup = (((V × V) × V) ∖ ran ((V ⊗ E ) △ (((◡1st ∘ E ) ∪ (◡2nd ∘ E )) ⊗ V)))
Definition	df-cap 36602	Define the little cap function. See brcap 36672 for its value. (Contributed by Scott Fenton, 17-Apr-2014.)
⊢ Cap = (((V × V) × V) ∖ ran ((V ⊗ E ) △ (((◡1st ∘ E ) ∩ (◡2nd ∘ E )) ⊗ V)))
Definition	df-restrict 36603	Define the restriction function. See brrestrict 36683 for its value. (Contributed by Scott Fenton, 17-Apr-2014.)
⊢ Restrict = (Cap ∘ (1st ⊗ (Cart ∘ (2nd ⊗ (Range ∘ 1st )))))
Definition	df-succf 36604	Define the successor function. See its alternate version dfsuccf2 36675. See brsuccf 36674 for its value. Cf. the equivalent df-sucmap 39362 family. (Contributed by Scott Fenton, 14-Apr-2014.)
⊢ Succ = (Cup ∘ ( I ⊗ Singleton))
Definition	df-apply 36605	Define the application function. See brapply 36670 for its value. (Contributed by Scott Fenton, 12-Apr-2014.)
⊢ Apply = (( Bigcup ∘ Bigcup ) ∘ (((V × V) ∖ ran ((V ⊗ E ) △ (( E ↾ Singletons ) ⊗ V))) ∘ ((Singleton ∘ Img) ∘ pprod( I , Singleton))))
Definition	df-funpart 36606	Define the functional part of a class 𝐹. This is the maximal part of 𝐹 that is a function. See funpartfun 36677 and funpartfv 36679 for the meaning of this statement. (Contributed by Scott Fenton, 16-Apr-2014.)
⊢ Funpart𝐹 = (𝐹 ↾ dom ((Image𝐹 ∘ Singleton) ∩ (V × Singletons )))
Definition	df-fullfun 36607	Define the full function over 𝐹. This is a function with domain V that always agrees with 𝐹 for its value. (Contributed by Scott Fenton, 17-Apr-2014.)
⊢ FullFun𝐹 = (Funpart𝐹 ∪ ((V ∖ dom Funpart𝐹) × {∅}))
Definition	df-ub 36608	Define the upper bound relationship functor. See brub 36688 for value. (Contributed by Scott Fenton, 3-May-2018.)
⊢ UB𝑅 = ((V × V) ∖ ((V ∖ 𝑅) ∘ ◡ E ))
Definition	df-lb 36609	Define the lower bound relationship functor. See brlb 36689 for value. (Contributed by Scott Fenton, 3-May-2018.)
⊢ LB𝑅 = UB◡𝑅
Theorem	txpss3v 36610	A tail Cartesian product is a subset of the class of ordered triples. (Contributed by Scott Fenton, 31-Mar-2012.)
⊢ (𝐴 ⊗ 𝐵) ⊆ (V × (V × V))
Theorem	txprel 36611	A tail Cartesian product is a relationship. (Contributed by Scott Fenton, 31-Mar-2012.)
⊢ Rel (𝐴 ⊗ 𝐵)
Theorem	brtxp 36612	Characterize a ternary relation over a tail Cartesian product. Together with txpss3v 36610, this completely defines membership in a tail cross. (Contributed by Scott Fenton, 31-Mar-2012.) (Proof shortened by Peter Mazsa, 2-Oct-2022.)
⊢ 𝑋 ∈ V    &   ⊢ 𝑌 ∈ V    &   ⊢ 𝑍 ∈ V    ⇒   ⊢ (𝑋(𝐴 ⊗ 𝐵)⟨𝑌, 𝑍⟩ ↔ (𝑋𝐴𝑌 ∧ 𝑋𝐵𝑍))
Theorem	brtxp2 36613*	The binary relation over a tail cross when the second argument is not an ordered pair. (Contributed by Scott Fenton, 14-Apr-2014.) (Revised by Mario Carneiro, 3-May-2015.)
⊢ 𝐴 ∈ V    ⇒   ⊢ (𝐴(𝑅 ⊗ 𝑆)𝐵 ↔ ∃𝑥∃𝑦(𝐵 = ⟨𝑥, 𝑦⟩ ∧ 𝐴𝑅𝑥 ∧ 𝐴𝑆𝑦))
Theorem	dfpprod2 36614	Expanded definition of parallel product. (Contributed by Scott Fenton, 3-May-2014.)
⊢ pprod(𝐴, 𝐵) = ((◡(1st ↾ (V × V)) ∘ (𝐴 ∘ (1st ↾ (V × V)))) ∩ (◡(2nd ↾ (V × V)) ∘ (𝐵 ∘ (2nd ↾ (V × V)))))
Theorem	pprodcnveq 36615	A converse law for parallel product. (Contributed by Scott Fenton, 3-May-2014.)
⊢ pprod(𝑅, 𝑆) = ◡pprod(◡𝑅, ◡𝑆)
Theorem	pprodss4v 36616	The parallel product is a subclass of ((V × V) × (V × V)). (Contributed by Scott Fenton, 11-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.) (Proof shortened by Peter Mazsa, 2-Oct-2022.)
⊢ pprod(𝐴, 𝐵) ⊆ ((V × V) × (V × V))
Theorem	brpprod 36617	Characterize a quaternary relation over a tail Cartesian product. Together with pprodss4v 36616, this completely defines membership in a parallel product. (Contributed by Scott Fenton, 11-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ 𝑋 ∈ V    &   ⊢ 𝑌 ∈ V    &   ⊢ 𝑍 ∈ V    &   ⊢ 𝑊 ∈ V    ⇒   ⊢ (⟨𝑋, 𝑌⟩pprod(𝐴, 𝐵)⟨𝑍, 𝑊⟩ ↔ (𝑋𝐴𝑍 ∧ 𝑌𝐵𝑊))
Theorem	brpprod3a 36618*	Condition for parallel product when the last argument is not an ordered pair. (Contributed by Scott Fenton, 11-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ 𝑋 ∈ V    &   ⊢ 𝑌 ∈ V    &   ⊢ 𝑍 ∈ V    ⇒   ⊢ (⟨𝑋, 𝑌⟩pprod(𝑅, 𝑆)𝑍 ↔ ∃𝑧∃𝑤(𝑍 = ⟨𝑧, 𝑤⟩ ∧ 𝑋𝑅𝑧 ∧ 𝑌𝑆𝑤))
Theorem	brpprod3b 36619*	Condition for parallel product when the first argument is not an ordered pair. (Contributed by Scott Fenton, 3-May-2014.)
⊢ 𝑋 ∈ V    &   ⊢ 𝑌 ∈ V    &   ⊢ 𝑍 ∈ V    ⇒   ⊢ (𝑋pprod(𝑅, 𝑆)⟨𝑌, 𝑍⟩ ↔ ∃𝑧∃𝑤(𝑋 = ⟨𝑧, 𝑤⟩ ∧ 𝑧𝑅𝑌 ∧ 𝑤𝑆𝑍))
Theorem	relsset 36620	The subset class is a binary relation. (Contributed by Scott Fenton, 31-Mar-2012.)
⊢ Rel SSet
Theorem	brsset 36621	For sets, the SSet binary relation is equivalent to the subset relationship. (Contributed by Scott Fenton, 31-Mar-2012.)
⊢ 𝐵 ∈ V    ⇒   ⊢ (𝐴 SSet 𝐵 ↔ 𝐴 ⊆ 𝐵)
Theorem	idsset 36622	I is equal to the intersection of SSet and its converse. (Contributed by Scott Fenton, 31-Mar-2012.)
⊢ I = ( SSet ∩ ◡ SSet )
Theorem	eltrans 36623	Membership in the class of all transitive sets. (Contributed by Scott Fenton, 31-Mar-2012.)
⊢ 𝐴 ∈ V    ⇒   ⊢ (𝐴 ∈ Trans ↔ Tr 𝐴)
Theorem	dfon3 36624	A quantifier-free definition of On. (Contributed by Scott Fenton, 5-Apr-2012.)
⊢ On = (V ∖ ran (( SSet ∩ ( Trans × V)) ∖ ( I ∪ E )))
Theorem	dfon4 36625	Another quantifier-free definition of On. (Contributed by Scott Fenton, 4-May-2014.)
⊢ On = (V ∖ (( SSet ∖ ( I ∪ E )) “ Trans ))
Theorem	brtxpsd 36626*	Expansion of a common form used in quantifier-free definitions. (Contributed by Scott Fenton, 17-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ 𝐴 ∈ V    &   ⊢ 𝐵 ∈ V    ⇒   ⊢ (¬ 𝐴ran ((V ⊗ E ) △ (𝑅 ⊗ V))𝐵 ↔ ∀𝑥(𝑥 ∈ 𝐵 ↔ 𝑥𝑅𝐴))
Theorem	brtxpsd2 36627*	Another common abbreviation for quantifier-free definitions. (Contributed by Scott Fenton, 21-Apr-2014.)
⊢ 𝐴 ∈ V    &   ⊢ 𝐵 ∈ V    &   ⊢ 𝑅 = (𝐶 ∖ ran ((V ⊗ E ) △ (𝑆 ⊗ V)))    &   ⊢ 𝐴𝐶𝐵    ⇒   ⊢ (𝐴𝑅𝐵 ↔ ∀𝑥(𝑥 ∈ 𝐵 ↔ 𝑥𝑆𝐴))
Theorem	brtxpsd3 36628*	A third common abbreviation for quantifier-free definitions. (Contributed by Scott Fenton, 3-May-2014.)
⊢ 𝐴 ∈ V    &   ⊢ 𝐵 ∈ V    &   ⊢ 𝑅 = (𝐶 ∖ ran ((V ⊗ E ) △ (𝑆 ⊗ V)))    &   ⊢ 𝐴𝐶𝐵    &   ⊢ (𝑥 ∈ 𝑋 ↔ 𝑥𝑆𝐴)    ⇒   ⊢ (𝐴𝑅𝐵 ↔ 𝐵 = 𝑋)
Theorem	relbigcup 36629	The Bigcup relationship is a relationship. (Contributed by Scott Fenton, 11-Apr-2012.)
⊢ Rel Bigcup
Theorem	brbigcup 36630	Binary relation over Bigcup . (Contributed by Scott Fenton, 11-Apr-2012.)
⊢ 𝐵 ∈ V    ⇒   ⊢ (𝐴 Bigcup 𝐵 ↔ ∪ 𝐴 = 𝐵)
Theorem	dfbigcup2 36631	Bigcup using maps-to notation. (Contributed by Scott Fenton, 16-Apr-2012.)
⊢ Bigcup = (𝑥 ∈ V ↦ ∪ 𝑥)
Theorem	fobigcup 36632	Bigcup maps the universe onto itself. (Contributed by Scott Fenton, 16-Apr-2012.)
⊢ Bigcup :V–onto→V
Theorem	fnbigcup 36633	Bigcup is a function over the universal class. (Contributed by Scott Fenton, 11-Apr-2012.)
⊢ Bigcup Fn V
Theorem	fvbigcup 36634	For sets, Bigcup yields union. (Contributed by Scott Fenton, 11-Apr-2012.)
⊢ 𝐴 ∈ V    ⇒   ⊢ ( Bigcup ‘𝐴) = ∪ 𝐴
Theorem	elfix 36635	Membership in the fixpoints of a class. (Contributed by Scott Fenton, 11-Apr-2012.)
⊢ 𝐴 ∈ V    ⇒   ⊢ (𝐴 ∈ Fix 𝑅 ↔ 𝐴𝑅𝐴)
Theorem	elfix2 36636	Alternative membership in the fixpoint of a class. (Contributed by Scott Fenton, 11-Apr-2012.)
⊢ Rel 𝑅    ⇒   ⊢ (𝐴 ∈ Fix 𝑅 ↔ 𝐴𝑅𝐴)
Theorem	dffix2 36637	The fixpoints of a class in terms of its range. (Contributed by Scott Fenton, 16-Apr-2012.)
⊢ Fix 𝐴 = ran (𝐴 ∩ I )
Theorem	fixssdm 36638	The fixpoints of a class are a subset of its domain. (Contributed by Scott Fenton, 16-Apr-2012.)
⊢ Fix 𝐴 ⊆ dom 𝐴
Theorem	fixssrn 36639	The fixpoints of a class are a subset of its range. (Contributed by Scott Fenton, 16-Apr-2012.)
⊢ Fix 𝐴 ⊆ ran 𝐴
Theorem	fixcnv 36640	The fixpoints of a class are the same as those of its converse. (Contributed by Scott Fenton, 16-Apr-2012.)
⊢ Fix 𝐴 = Fix ◡𝐴
Theorem	fixun 36641	The fixpoint operator distributes over union. (Contributed by Scott Fenton, 16-Apr-2012.)
⊢ Fix (𝐴 ∪ 𝐵) = ( Fix 𝐴 ∪ Fix 𝐵)
Theorem	ellimits 36642	Membership in the class of all limit ordinals. (Contributed by Scott Fenton, 11-Apr-2012.)
⊢ 𝐴 ∈ V    ⇒   ⊢ (𝐴 ∈ Limits ↔ Lim 𝐴)
Theorem	limitssson 36643	The class of all limit ordinals is a subclass of the class of all ordinals. (Contributed by Scott Fenton, 11-Apr-2012.)
⊢ Limits ⊆ On
Theorem	dfom5b 36644	A quantifier-free definition of ω that does not depend on ax-inf 9623. (Note: label was changed from dfom5 9635 to dfom5b 36644 to prevent naming conflict. NM, 12-Feb-2013.) (Contributed by Scott Fenton, 11-Apr-2012.)
⊢ ω = (On ∩ ∩ Limits )
Theorem	sscoid 36645	A condition for subset and composition with identity. (Contributed by Scott Fenton, 13-Apr-2018.)
⊢ (𝐴 ⊆ ( I ∘ 𝐵) ↔ (Rel 𝐴 ∧ 𝐴 ⊆ 𝐵))
Theorem	dffun10 36646	Another potential definition of functionality. Based on statements in http://people.math.gatech.edu/~belinfan/research/autoreas/otter/sum/fs/. (Contributed by Scott Fenton, 30-Aug-2017.)
⊢ (Fun 𝐹 ↔ 𝐹 ⊆ ( I ∘ (V ∖ ((V ∖ I ) ∘ 𝐹))))
Theorem	elfuns 36647	Membership in the class of all functions. (Contributed by Scott Fenton, 18-Feb-2013.)
⊢ 𝐹 ∈ V    ⇒   ⊢ (𝐹 ∈ Funs ↔ Fun 𝐹)
Theorem	elfunsg 36648	Closed form of elfuns 36647. (Contributed by Scott Fenton, 2-May-2014.)
⊢ (𝐹 ∈ 𝑉 → (𝐹 ∈ Funs ↔ Fun 𝐹))
Theorem	brsingle 36649	The binary relation form of the singleton function. (Contributed by Scott Fenton, 4-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ 𝐴 ∈ V    &   ⊢ 𝐵 ∈ V    ⇒   ⊢ (𝐴Singleton𝐵 ↔ 𝐵 = {𝐴})
Theorem	elsingles 36650*	Membership in the class of all singletons. (Contributed by Scott Fenton, 19-Feb-2013.)
⊢ (𝐴 ∈ Singletons ↔ ∃𝑥 𝐴 = {𝑥})
Theorem	fnsingle 36651	The singleton relationship is a function over the universe. (Contributed by Scott Fenton, 4-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ Singleton Fn V
Theorem	fvsingle 36652	The value of the singleton function. (Contributed by Scott Fenton, 4-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.) (Revised by Scott Fenton, 13-Apr-2018.)
⊢ (Singleton‘𝐴) = {𝐴}
Theorem	dfsingles2 36653*	Alternate definition of the class of all singletons. (Contributed by Scott Fenton, 20-Nov-2013.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ Singletons = {𝑥 ∣ ∃𝑦 𝑥 = {𝑦}}
Theorem	snelsingles 36654	A singleton is a member of the class of all singletons. (Contributed by Scott Fenton, 19-Feb-2013.)
⊢ 𝐴 ∈ V    ⇒   ⊢ {𝐴} ∈ Singletons
Theorem	dfiota3 36655	A definition of iota using minimal quantifiers. (Contributed by Scott Fenton, 19-Feb-2013.)
⊢ (℩𝑥𝜑) = ∪ ∪ ({{𝑥 ∣ 𝜑}} ∩ Singletons )
Theorem	dffv5 36656	Another quantifier-free definition of function value. (Contributed by Scott Fenton, 19-Feb-2013.)
⊢ (𝐹‘𝐴) = ∪ ∪ ({(𝐹 “ {𝐴})} ∩ Singletons )
Theorem	unisnif 36657	Express union of singleton in terms of if. (Contributed by Scott Fenton, 27-Mar-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ ∪ {𝐴} = if(𝐴 ∈ V, 𝐴, ∅)
Theorem	brimage 36658	Binary relation form of the Image functor. (Contributed by Scott Fenton, 4-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ 𝐴 ∈ V    &   ⊢ 𝐵 ∈ V    ⇒   ⊢ (𝐴Image𝑅𝐵 ↔ 𝐵 = (𝑅 “ 𝐴))
Theorem	brimageg 36659	Closed form of brimage 36658. (Contributed by Scott Fenton, 4-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → (𝐴Image𝑅𝐵 ↔ 𝐵 = (𝑅 “ 𝐴)))
Theorem	funimage 36660	Image𝐴 is a function. (Contributed by Scott Fenton, 27-Mar-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ Fun Image𝐴
Theorem	fnimage 36661*	Image𝑅 is a function over the set-like portion of 𝑅. (Contributed by Scott Fenton, 4-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ Image𝑅 Fn {𝑥 ∣ (𝑅 “ 𝑥) ∈ V}
Theorem	imageval 36662*	The image functor in maps-to notation. (Contributed by Scott Fenton, 4-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ Image𝑅 = (𝑥 ∈ V ↦ (𝑅 “ 𝑥))
Theorem	fvimage 36663	Value of the image functor. (Contributed by Scott Fenton, 4-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ ((𝐴 ∈ 𝑉 ∧ (𝑅 “ 𝐴) ∈ 𝑊) → (Image𝑅‘𝐴) = (𝑅 “ 𝐴))
Theorem	brcart 36664	Binary relation form of the cartesian product operator. (Contributed by Scott Fenton, 11-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ 𝐴 ∈ V    &   ⊢ 𝐵 ∈ V    &   ⊢ 𝐶 ∈ V    ⇒   ⊢ (⟨𝐴, 𝐵⟩Cart𝐶 ↔ 𝐶 = (𝐴 × 𝐵))
Theorem	brdomain 36665	Binary relation form of the domain function. (Contributed by Scott Fenton, 11-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ 𝐴 ∈ V    &   ⊢ 𝐵 ∈ V    ⇒   ⊢ (𝐴Domain𝐵 ↔ 𝐵 = dom 𝐴)
Theorem	brrange 36666	Binary relation form of the range function. (Contributed by Scott Fenton, 11-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ 𝐴 ∈ V    &   ⊢ 𝐵 ∈ V    ⇒   ⊢ (𝐴Range𝐵 ↔ 𝐵 = ran 𝐴)
Theorem	brdomaing 36667	Closed form of brdomain 36665. (Contributed by Scott Fenton, 2-May-2014.)
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → (𝐴Domain𝐵 ↔ 𝐵 = dom 𝐴))
Theorem	brrangeg 36668	Closed form of brrange 36666. (Contributed by Scott Fenton, 3-May-2014.)
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → (𝐴Range𝐵 ↔ 𝐵 = ran 𝐴))
Theorem	brimg 36669	Binary relation form of the Img function. (Contributed by Scott Fenton, 12-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.) (Proof shortened by Peter Mazsa, 2-Oct-2022.)
⊢ 𝐴 ∈ V    &   ⊢ 𝐵 ∈ V    &   ⊢ 𝐶 ∈ V    ⇒   ⊢ (⟨𝐴, 𝐵⟩Img𝐶 ↔ 𝐶 = (𝐴 “ 𝐵))
Theorem	brapply 36670	Binary relation form of the Apply function. (Contributed by Scott Fenton, 12-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.) (Proof shortened by Peter Mazsa, 2-Oct-2022.)
⊢ 𝐴 ∈ V    &   ⊢ 𝐵 ∈ V    &   ⊢ 𝐶 ∈ V    ⇒   ⊢ (⟨𝐴, 𝐵⟩Apply𝐶 ↔ 𝐶 = (𝐴‘𝐵))
Theorem	brcup 36671	Binary relation form of the Cup function. (Contributed by Scott Fenton, 14-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ 𝐴 ∈ V    &   ⊢ 𝐵 ∈ V    &   ⊢ 𝐶 ∈ V    ⇒   ⊢ (⟨𝐴, 𝐵⟩Cup𝐶 ↔ 𝐶 = (𝐴 ∪ 𝐵))
Theorem	brcap 36672	Binary relation form of the Cap function. (Contributed by Scott Fenton, 17-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ 𝐴 ∈ V    &   ⊢ 𝐵 ∈ V    &   ⊢ 𝐶 ∈ V    ⇒   ⊢ (⟨𝐴, 𝐵⟩Cap𝐶 ↔ 𝐶 = (𝐴 ∩ 𝐵))
Theorem	lemsuccf 36673*	Lemma for unfolding different forms of the Succ function. (Contributed by Scott Fenton, 14-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ 𝐴 ∈ V    &   ⊢ 𝐵 ∈ V    ⇒   ⊢ (∃𝑥(𝐴( I ⊗ Singleton)𝑥 ∧ 𝑥Cup𝐵) ↔ 𝐵 = suc 𝐴)
Theorem	brsuccf 36674	Binary relation form of the Succ function. (Contributed by Scott Fenton, 14-Apr-2014.)
⊢ 𝐴 ∈ V    &   ⊢ 𝐵 ∈ V    ⇒   ⊢ (𝐴Succ𝐵 ↔ 𝐵 = suc 𝐴)
Theorem	dfsuccf2 36675*	Alternate definition of Scott Fenton's version of Succ, cf. df-sucmap 39362. (Contributed by Peter Mazsa, 6-Jan-2026.)
⊢ Succ = {⟨𝑚, 𝑛⟩ ∣ suc 𝑚 = 𝑛}
Theorem	funpartlem 36676*	Lemma for funpartfun 36677. Show membership in the restriction. (Contributed by Scott Fenton, 4-Dec-2017.)
⊢ (𝐴 ∈ dom ((Image𝐹 ∘ Singleton) ∩ (V × Singletons )) ↔ ∃𝑥(𝐹 “ {𝐴}) = {𝑥})
Theorem	funpartfun 36677	The functional part of 𝐹 is a function. (Contributed by Scott Fenton, 16-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.) (Proof shortened by Peter Mazsa, 2-Oct-2022.)
⊢ Fun Funpart𝐹
Theorem	funpartss 36678	The functional part of 𝐹 is a subset of 𝐹. (Contributed by Scott Fenton, 17-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ Funpart𝐹 ⊆ 𝐹
Theorem	funpartfv 36679	The function value of the functional part is identical to the original functional value. (Contributed by Scott Fenton, 17-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ (Funpart𝐹‘𝐴) = (𝐹‘𝐴)
Theorem	fullfunfnv 36680	The full functional part of 𝐹 is a function over V. (Contributed by Scott Fenton, 17-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ FullFun𝐹 Fn V
Theorem	fullfunfv 36681	The function value of the full function of 𝐹 agrees with 𝐹. (Contributed by Scott Fenton, 17-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ (FullFun𝐹‘𝐴) = (𝐹‘𝐴)
Theorem	brfullfun 36682	A binary relation form condition for the full function. (Contributed by Scott Fenton, 17-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ 𝐴 ∈ V    &   ⊢ 𝐵 ∈ V    ⇒   ⊢ (𝐴FullFun𝐹𝐵 ↔ 𝐵 = (𝐹‘𝐴))
Theorem	brrestrict 36683	Binary relation form of the Restrict function. (Contributed by Scott Fenton, 17-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
⊢ 𝐴 ∈ V    &   ⊢ 𝐵 ∈ V    &   ⊢ 𝐶 ∈ V    ⇒   ⊢ (⟨𝐴, 𝐵⟩Restrict𝐶 ↔ 𝐶 = (𝐴 ↾ 𝐵))
Theorem	dfrecs2 36684	A quantifier-free definition of recs. (Contributed by Scott Fenton, 17-Jul-2020.)
⊢ recs(𝐹) = ∪ (( Funs ∩ (◡Domain “ On)) ∖ dom ((◡ E ∘ Domain) ∖ Fix (◡Apply ∘ (FullFun𝐹 ∘ Restrict))))
Theorem	dfrdg4 36685	A quantifier-free definition of the recursive definition generator. (Contributed by Scott Fenton, 17-Apr-2014.) (Revised by Mario Carneiro, 19-Apr-2014.) (Proof shortened by Peter Mazsa, 2-Oct-2022.)
⊢ rec(𝐹, 𝐴) = ∪ (( Funs ∩ (◡Domain “ On)) ∖ dom ((◡ E ∘ Domain) ∖ Fix (◡Apply ∘ (((V × {∅}) × {∪ {𝐴}}) ∪ ((( Bigcup ∘ Img) ↾ (V × Limits )) ∪ ((FullFun𝐹 ∘ (Apply ∘ pprod( I , Bigcup ))) ↾ (V × ran Succ)))))))
Theorem	dfint3 36686	Quantifier-free definition of class intersection. (Contributed by Scott Fenton, 13-Apr-2018.)
⊢ ∩ 𝐴 = (V ∖ (◡(V ∖ E ) “ 𝐴))
Theorem	imagesset 36687	The Image functor applied to the converse of the subset relationship yields a subset of the subset relationship. (Contributed by Scott Fenton, 14-Apr-2018.)
⊢ Image◡ SSet ⊆ SSet
Theorem	brub 36688*	Binary relation form of the upper bound functor. (Contributed by Scott Fenton, 3-May-2018.)
⊢ 𝑆 ∈ V    &   ⊢ 𝐴 ∈ V    ⇒   ⊢ (𝑆UB𝑅𝐴 ↔ ∀𝑥 ∈ 𝑆 𝑥𝑅𝐴)
Theorem	brlb 36689*	Binary relation form of the lower bound functor. (Contributed by Scott Fenton, 3-May-2018.)
⊢ 𝑆 ∈ V    &   ⊢ 𝐴 ∈ V    ⇒   ⊢ (𝑆LB𝑅𝐴 ↔ ∀𝑥 ∈ 𝑆 𝐴𝑅𝑥)
Theorem	dffr7 36690	Alternate quantifier-free definition of a well-founded relation. (Contributed by Scott Fenton, 26-Aug-2026.)
⊢ (𝑅 Fr 𝐴 ↔ (𝒫 𝐴 ∖ {∅}) ⊆ Fix ( E ∘ (V ∖ (𝑅 ∘ ◡ E ))))
21.11.16  Alternate ordered pairs
Syntax	caltop 36691	Declare the syntax for an alternate ordered pair.
class ⟪𝐴, 𝐵⟫
Syntax	caltxp 36692	Declare the syntax for an alternate Cartesian product.
class (𝐴 ×× 𝐵)
Definition	df-altop 36693	An alternative definition of ordered pairs. This definition removes a hypothesis from its defining theorem (see altopth 36704), making it more convenient in some circumstances. (Contributed by Scott Fenton, 22-Mar-2012.)
⊢ ⟪𝐴, 𝐵⟫ = {{𝐴}, {𝐴, {𝐵}}}
Definition	df-altxp 36694*	Define Cartesian products of alternative ordered pairs. (Contributed by Scott Fenton, 23-Mar-2012.)
⊢ (𝐴 ×× 𝐵) = {𝑧 ∣ ∃𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝑧 = ⟪𝑥, 𝑦⟫}
Theorem	altopex 36695	Alternative ordered pairs always exist. (Contributed by Scott Fenton, 22-Mar-2012.)
⊢ ⟪𝐴, 𝐵⟫ ∈ V
Theorem	altopthsn 36696	Two alternate ordered pairs are equal iff the singletons of their respective elements are equal. Note that this holds regardless of sethood of any of the elements. (Contributed by Scott Fenton, 16-Apr-2012.)
⊢ (⟪𝐴, 𝐵⟫ = ⟪𝐶, 𝐷⟫ ↔ ({𝐴} = {𝐶} ∧ {𝐵} = {𝐷}))
Theorem	altopeq12 36697	Equality for alternate ordered pairs. (Contributed by Scott Fenton, 22-Mar-2012.)
⊢ ((𝐴 = 𝐵 ∧ 𝐶 = 𝐷) → ⟪𝐴, 𝐶⟫ = ⟪𝐵, 𝐷⟫)
Theorem	altopeq1 36698	Equality for alternate ordered pairs. (Contributed by Scott Fenton, 22-Mar-2012.)
⊢ (𝐴 = 𝐵 → ⟪𝐴, 𝐶⟫ = ⟪𝐵, 𝐶⟫)
Theorem	altopeq2 36699	Equality for alternate ordered pairs. (Contributed by Scott Fenton, 22-Mar-2012.)
⊢ (𝐴 = 𝐵 → ⟪𝐶, 𝐴⟫ = ⟪𝐶, 𝐵⟫)
Theorem	altopth1 36700	Equality of the first members of equal alternate ordered pairs, which holds regardless of the second members' sethood. (Contributed by Scott Fenton, 22-Mar-2012.)
⊢ (𝐴 ∈ 𝑉 → (⟪𝐴, 𝐵⟫ = ⟪𝐶, 𝐷⟫ → 𝐴 = 𝐶))