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Type | Label | Description |
---|---|---|
Statement | ||
Theorem | unbnn 8101* | Any unbounded subset of natural numbers is equinumerous to the set of all natural numbers. Part of the proof of Theorem 42 of [Suppes] p. 151. See unbnn3 8439 for a stronger version without the first assumption. (Contributed by NM, 3-Dec-2003.) |
⊢ ((ω ∈ V ∧ 𝐴 ⊆ ω ∧ ∀𝑥 ∈ ω ∃𝑦 ∈ 𝐴 𝑥 ∈ 𝑦) → 𝐴 ≈ ω) | ||
Theorem | unbnn2 8102* | Version of unbnn 8101 that does not require a strict upper bound. (Contributed by NM, 24-Apr-2004.) |
⊢ ((ω ∈ V ∧ 𝐴 ⊆ ω ∧ ∀𝑥 ∈ ω ∃𝑦 ∈ 𝐴 𝑥 ⊆ 𝑦) → 𝐴 ≈ ω) | ||
Theorem | isfinite2 8103 | Any set strictly dominated by the class of natural numbers is finite. Sufficiency part of Theorem 42 of [Suppes] p. 151. This theorem does not require the Axiom of Infinity. (Contributed by NM, 24-Apr-2004.) |
⊢ (𝐴 ≺ ω → 𝐴 ∈ Fin) | ||
Theorem | nnsdomg 8104 | Omega strictly dominates a natural number. Example 3 of [Enderton] p. 146. In order to avoid the Axiom of infinity, we include it as a hypothesis. (Contributed by NM, 15-Jun-1998.) |
⊢ ((ω ∈ V ∧ 𝐴 ∈ ω) → 𝐴 ≺ ω) | ||
Theorem | isfiniteg 8105 | A set is finite iff it is strictly dominated by the class of natural number. Theorem 42 of [Suppes] p. 151. In order to avoid the Axiom of infinity, we include it as a hypothesis. (Contributed by NM, 3-Nov-2002.) (Revised by Mario Carneiro, 27-Apr-2015.) |
⊢ (ω ∈ V → (𝐴 ∈ Fin ↔ 𝐴 ≺ ω)) | ||
Theorem | infsdomnn 8106 | An infinite set strictly dominates a natural number. (Contributed by NM, 22-Nov-2004.) (Revised by Mario Carneiro, 27-Apr-2015.) |
⊢ ((ω ≼ 𝐴 ∧ 𝐵 ∈ ω) → 𝐵 ≺ 𝐴) | ||
Theorem | infn0 8107 | An infinite set is not empty. (Contributed by NM, 23-Oct-2004.) |
⊢ (ω ≼ 𝐴 → 𝐴 ≠ ∅) | ||
Theorem | fin2inf 8108 | This (useless) theorem, which was proved without the Axiom of Infinity, demonstrates an artifact of our definition of binary relation, which is meaningful only when its arguments exist. In particular, the antecedent cannot be satisfied unless ω exists. (Contributed by NM, 13-Nov-2003.) |
⊢ (𝐴 ≺ ω → ω ∈ V) | ||
Theorem | unfilem1 8109* | Lemma for proving that the union of two finite sets is finite. (Contributed by NM, 10-Nov-2002.) (Revised by Mario Carneiro, 31-Aug-2015.) |
⊢ 𝐴 ∈ ω & ⊢ 𝐵 ∈ ω & ⊢ 𝐹 = (𝑥 ∈ 𝐵 ↦ (𝐴 +𝑜 𝑥)) ⇒ ⊢ ran 𝐹 = ((𝐴 +𝑜 𝐵) ∖ 𝐴) | ||
Theorem | unfilem2 8110* | Lemma for proving that the union of two finite sets is finite. (Contributed by NM, 10-Nov-2002.) (Revised by Mario Carneiro, 31-Aug-2015.) |
⊢ 𝐴 ∈ ω & ⊢ 𝐵 ∈ ω & ⊢ 𝐹 = (𝑥 ∈ 𝐵 ↦ (𝐴 +𝑜 𝑥)) ⇒ ⊢ 𝐹:𝐵–1-1-onto→((𝐴 +𝑜 𝐵) ∖ 𝐴) | ||
Theorem | unfilem3 8111 | Lemma for proving that the union of two finite sets is finite. (Contributed by NM, 16-Nov-2002.) (Revised by Mario Carneiro, 31-Aug-2015.) |
⊢ ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → 𝐵 ≈ ((𝐴 +𝑜 𝐵) ∖ 𝐴)) | ||
Theorem | unfi 8112 | The union of two finite sets is finite. Part of Corollary 6K of [Enderton] p. 144. (Contributed by NM, 16-Nov-2002.) |
⊢ ((𝐴 ∈ Fin ∧ 𝐵 ∈ Fin) → (𝐴 ∪ 𝐵) ∈ Fin) | ||
Theorem | unfir 8113 | If a union is finite, the operands are finite. Converse of unfi 8112. (Contributed by FL, 3-Aug-2009.) |
⊢ ((𝐴 ∪ 𝐵) ∈ Fin → (𝐴 ∈ Fin ∧ 𝐵 ∈ Fin)) | ||
Theorem | unfi2 8114 | The union of two finite sets is finite. Part of Corollary 6K of [Enderton] p. 144. This version of unfi 8112 is useful only if we assume the Axiom of Infinity (see comments in fin2inf 8108). (Contributed by NM, 22-Oct-2004.) (Revised by Mario Carneiro, 27-Apr-2015.) |
⊢ ((𝐴 ≺ ω ∧ 𝐵 ≺ ω) → (𝐴 ∪ 𝐵) ≺ ω) | ||
Theorem | difinf 8115 | An infinite set 𝐴 minus a finite set is infinite. (Contributed by FL, 3-Aug-2009.) |
⊢ ((¬ 𝐴 ∈ Fin ∧ 𝐵 ∈ Fin) → ¬ (𝐴 ∖ 𝐵) ∈ Fin) | ||
Theorem | xpfi 8116 | The Cartesian product of two finite sets is finite. (Contributed by Jeff Madsen, 2-Sep-2009.) (Revised by Mario Carneiro, 12-Mar-2015.) |
⊢ ((𝐴 ∈ Fin ∧ 𝐵 ∈ Fin) → (𝐴 × 𝐵) ∈ Fin) | ||
Theorem | 3xpfi 8117 | The Cartesian product of three finite sets is a finite set. (Contributed by Alexander van der Vekens, 11-Mar-2018.) |
⊢ (𝑉 ∈ Fin → ((𝑉 × 𝑉) × 𝑉) ∈ Fin) | ||
Theorem | domunfican 8118 | A finite set union cancellation law for dominance. (Contributed by Stefan O'Rear, 19-Feb-2015.) (Revised by Stefan O'Rear, 5-May-2015.) |
⊢ (((𝐴 ∈ Fin ∧ 𝐵 ≈ 𝐴) ∧ ((𝐴 ∩ 𝑋) = ∅ ∧ (𝐵 ∩ 𝑌) = ∅)) → ((𝐴 ∪ 𝑋) ≼ (𝐵 ∪ 𝑌) ↔ 𝑋 ≼ 𝑌)) | ||
Theorem | infcntss 8119* | Every infinite set has a denumerable subset. Similar to Exercise 8 of [TakeutiZaring] p. 91. (However, we need neither AC nor the Axiom of Infinity because of the way we express "infinite" in the antecedent.) (Contributed by NM, 23-Oct-2004.) |
⊢ 𝐴 ∈ V ⇒ ⊢ (ω ≼ 𝐴 → ∃𝑥(𝑥 ⊆ 𝐴 ∧ 𝑥 ≈ ω)) | ||
Theorem | prfi 8120 | An unordered pair is finite. (Contributed by NM, 22-Aug-2008.) |
⊢ {𝐴, 𝐵} ∈ Fin | ||
Theorem | tpfi 8121 | An unordered triple is finite. (Contributed by Mario Carneiro, 28-Sep-2013.) |
⊢ {𝐴, 𝐵, 𝐶} ∈ Fin | ||
Theorem | fiint 8122* | Equivalent ways of stating the finite intersection property. We show two ways of saying, "the intersection of elements in every finite nonempty subcollection of 𝐴 is in 𝐴." This theorem is applicable to a topology, which (among other axioms) is closed under finite intersections. Some texts use the left-hand version of this axiom and others the right-hand version, but as our proof here shows, their "intuitively obvious" equivalence can be non-trivial to establish formally. (Contributed by NM, 22-Sep-2002.) |
⊢ (∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝑥 ∩ 𝑦) ∈ 𝐴 ↔ ∀𝑥((𝑥 ⊆ 𝐴 ∧ 𝑥 ≠ ∅ ∧ 𝑥 ∈ Fin) → ∩ 𝑥 ∈ 𝐴)) | ||
Theorem | fnfi 8123 | A version of fnex 6386 for finite sets that does not require Replacement. (Contributed by Mario Carneiro, 16-Nov-2014.) (Revised by Mario Carneiro, 24-Jun-2015.) |
⊢ ((𝐹 Fn 𝐴 ∧ 𝐴 ∈ Fin) → 𝐹 ∈ Fin) | ||
Theorem | fodomfi 8124 | An onto function implies dominance of domain over range, for finite sets. Unlike fodom 9227 for arbitrary sets, this theorem does not require the Axiom of Choice for its proof. (Contributed by NM, 23-Mar-2006.) (Proof shortened by Mario Carneiro, 16-Nov-2014.) |
⊢ ((𝐴 ∈ Fin ∧ 𝐹:𝐴–onto→𝐵) → 𝐵 ≼ 𝐴) | ||
Theorem | fodomfib 8125* | Equivalence of an onto mapping and dominance for a nonempty finite set. Unlike fodomb 9229 for arbitrary sets, this theorem does not require the Axiom of Choice for its proof. (Contributed by NM, 23-Mar-2006.) |
⊢ (𝐴 ∈ Fin → ((𝐴 ≠ ∅ ∧ ∃𝑓 𝑓:𝐴–onto→𝐵) ↔ (∅ ≺ 𝐵 ∧ 𝐵 ≼ 𝐴))) | ||
Theorem | fofinf1o 8126 | Any surjection from one finite set to another of equal size must be a bijection. (Contributed by Mario Carneiro, 19-Aug-2014.) |
⊢ ((𝐹:𝐴–onto→𝐵 ∧ 𝐴 ≈ 𝐵 ∧ 𝐵 ∈ Fin) → 𝐹:𝐴–1-1-onto→𝐵) | ||
Theorem | rneqdmfinf1o 8127 | Any function from a finite set onto the same set must be a bijection. (Contributed by AV, 5-Jul-2021.) |
⊢ ((𝐴 ∈ Fin ∧ 𝐹 Fn 𝐴 ∧ ran 𝐹 = 𝐴) → 𝐹:𝐴–1-1-onto→𝐴) | ||
Theorem | fidomdm 8128 | Any finite set dominates its domain. (Contributed by Mario Carneiro, 22-Sep-2013.) (Revised by Mario Carneiro, 16-Nov-2014.) |
⊢ (𝐹 ∈ Fin → dom 𝐹 ≼ 𝐹) | ||
Theorem | dmfi 8129 | The domain of a finite set is finite. (Contributed by Mario Carneiro, 24-Sep-2013.) |
⊢ (𝐴 ∈ Fin → dom 𝐴 ∈ Fin) | ||
Theorem | fundmfibi 8130 | A function (set) is finite if and only if its domain is finite. (Contributed by AV, 10-Jan-2020.) |
⊢ (Fun 𝐹 → (𝐹 ∈ Fin ↔ dom 𝐹 ∈ Fin)) | ||
Theorem | cnvfi 8131 | If a set is finite, its converse is as well. (Contributed by Mario Carneiro, 28-Dec-2014.) |
⊢ (𝐴 ∈ Fin → ◡𝐴 ∈ Fin) | ||
Theorem | rnfi 8132 | The range of a finite set is finite. (Contributed by Mario Carneiro, 28-Dec-2014.) |
⊢ (𝐴 ∈ Fin → ran 𝐴 ∈ Fin) | ||
Theorem | f1dmvrnfibi 8133 | A 1-1 function (class) with a set as domain is finite if and only if its range is finite. (Contributed by AV, 10-Jan-2020.) |
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴–1-1→𝐵) → (𝐹 ∈ Fin ↔ ran 𝐹 ∈ Fin)) | ||
Theorem | f1vrnfibi 8134 | A 1-1 function (set) is finite if and only if its range is finite. (Contributed by AV, 10-Jan-2020.) |
⊢ ((𝐹 ∈ 𝑉 ∧ 𝐹:𝐴–1-1→𝐵) → (𝐹 ∈ Fin ↔ ran 𝐹 ∈ Fin)) | ||
Theorem | fofi 8135 | If a function has a finite domain, its range is finite. Theorem 37 of [Suppes] p. 104. (Contributed by NM, 25-Mar-2007.) |
⊢ ((𝐴 ∈ Fin ∧ 𝐹:𝐴–onto→𝐵) → 𝐵 ∈ Fin) | ||
Theorem | f1fi 8136 | If a 1-to-1 function has a finite codomain its domain is finite. (Contributed by FL, 31-Jul-2009.) (Revised by Mario Carneiro, 24-Jun-2015.) |
⊢ ((𝐵 ∈ Fin ∧ 𝐹:𝐴–1-1→𝐵) → 𝐴 ∈ Fin) | ||
Theorem | iunfi 8137* | The finite union of finite sets is finite. Exercise 13 of [Enderton] p. 144. This is the indexed union version of unifi 8138. Note that 𝐵 depends on 𝑥, i.e. can be thought of as 𝐵(𝑥). (Contributed by NM, 23-Mar-2006.) (Proof shortened by Mario Carneiro, 31-Aug-2015.) |
⊢ ((𝐴 ∈ Fin ∧ ∀𝑥 ∈ 𝐴 𝐵 ∈ Fin) → ∪ 𝑥 ∈ 𝐴 𝐵 ∈ Fin) | ||
Theorem | unifi 8138 | The finite union of finite sets is finite. Exercise 13 of [Enderton] p. 144. (Contributed by NM, 22-Aug-2008.) (Revised by Mario Carneiro, 31-Aug-2015.) |
⊢ ((𝐴 ∈ Fin ∧ 𝐴 ⊆ Fin) → ∪ 𝐴 ∈ Fin) | ||
Theorem | unifi2 8139* | The finite union of finite sets is finite. Exercise 13 of [Enderton] p. 144. This version of unifi 8138 is useful only if we assume the Axiom of Infinity (see comments in fin2inf 8108). (Contributed by NM, 11-Mar-2006.) |
⊢ ((𝐴 ≺ ω ∧ ∀𝑥 ∈ 𝐴 𝑥 ≺ ω) → ∪ 𝐴 ≺ ω) | ||
Theorem | infssuni 8140* | If an infinite set 𝐴 is included in the underlying set of a finite cover 𝐵, then there exists a set of the cover that contains an infinite number of element of 𝐴. (Contributed by FL, 2-Aug-2009.) |
⊢ ((¬ 𝐴 ∈ Fin ∧ 𝐵 ∈ Fin ∧ 𝐴 ⊆ ∪ 𝐵) → ∃𝑥 ∈ 𝐵 ¬ (𝐴 ∩ 𝑥) ∈ Fin) | ||
Theorem | unirnffid 8141 | The union of the range of a function from a finite set into the class of finite sets is finite. Deduction form. (Contributed by David Moews, 1-May-2017.) |
⊢ (𝜑 → 𝐹:𝑇⟶Fin) & ⊢ (𝜑 → 𝑇 ∈ Fin) ⇒ ⊢ (𝜑 → ∪ ran 𝐹 ∈ Fin) | ||
Theorem | imafi 8142 | Images of finite sets are finite. (Contributed by Stefan O'Rear, 22-Feb-2015.) |
⊢ ((Fun 𝐹 ∧ 𝑋 ∈ Fin) → (𝐹 “ 𝑋) ∈ Fin) | ||
Theorem | pwfilem 8143* | Lemma for pwfi 8144. (Contributed by NM, 26-Mar-2007.) |
⊢ 𝐹 = (𝑐 ∈ 𝒫 𝑏 ↦ (𝑐 ∪ {𝑥})) ⇒ ⊢ (𝒫 𝑏 ∈ Fin → 𝒫 (𝑏 ∪ {𝑥}) ∈ Fin) | ||
Theorem | pwfi 8144 | The power set of a finite set is finite and vice-versa. Theorem 38 of [Suppes] p. 104 and its converse, Theorem 40 of [Suppes] p. 105. (Contributed by NM, 26-Mar-2007.) |
⊢ (𝐴 ∈ Fin ↔ 𝒫 𝐴 ∈ Fin) | ||
Theorem | mapfi 8145 | Set exponentiation of finite sets is finite. (Contributed by Jeff Madsen, 19-Jun-2011.) |
⊢ ((𝐴 ∈ Fin ∧ 𝐵 ∈ Fin) → (𝐴 ↑𝑚 𝐵) ∈ Fin) | ||
Theorem | ixpfi 8146* | A Cartesian product of finitely many finite sets is finite. (Contributed by Jeff Madsen, 19-Jun-2011.) |
⊢ ((𝐴 ∈ Fin ∧ ∀𝑥 ∈ 𝐴 𝐵 ∈ Fin) → X𝑥 ∈ 𝐴 𝐵 ∈ Fin) | ||
Theorem | ixpfi2 8147* | A Cartesian product of finite sets such that all but finitely many are singletons is finite. (Note that 𝐵(𝑥) and 𝐷(𝑥) are both possibly dependent on 𝑥.) (Contributed by Mario Carneiro, 25-Jan-2015.) |
⊢ (𝜑 → 𝐶 ∈ Fin) & ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → 𝐵 ∈ Fin) & ⊢ ((𝜑 ∧ 𝑥 ∈ (𝐴 ∖ 𝐶)) → 𝐵 ⊆ {𝐷}) ⇒ ⊢ (𝜑 → X𝑥 ∈ 𝐴 𝐵 ∈ Fin) | ||
Theorem | mptfi 8148* | A finite mapping set is finite. (Contributed by Mario Carneiro, 31-Aug-2015.) |
⊢ (𝐴 ∈ Fin → (𝑥 ∈ 𝐴 ↦ 𝐵) ∈ Fin) | ||
Theorem | abrexfi 8149* | An image set from a finite set is finite. (Contributed by Mario Carneiro, 13-Feb-2014.) |
⊢ (𝐴 ∈ Fin → {𝑦 ∣ ∃𝑥 ∈ 𝐴 𝑦 = 𝐵} ∈ Fin) | ||
Theorem | cnvimamptfin 8150* | A preimage of a mapping with a finite domain under any class is finite. In contrast to fisuppfi 8166, the range of the mapping needs not to be known. (Contributed by AV, 21-Dec-2018.) |
⊢ (𝜑 → 𝑁 ∈ Fin) ⇒ ⊢ (𝜑 → (◡(𝑝 ∈ 𝑁 ↦ 𝑋) “ 𝑌) ∈ Fin) | ||
Theorem | elfpw 8151 | Membership in a class of finite subsets. (Contributed by Stefan O'Rear, 4-Apr-2015.) (Revised by Mario Carneiro, 22-Aug-2015.) |
⊢ (𝐴 ∈ (𝒫 𝐵 ∩ Fin) ↔ (𝐴 ⊆ 𝐵 ∧ 𝐴 ∈ Fin)) | ||
Theorem | unifpw 8152 | A set is the union of its finite subsets. (Contributed by Stefan O'Rear, 2-Apr-2015.) |
⊢ ∪ (𝒫 𝐴 ∩ Fin) = 𝐴 | ||
Theorem | f1opwfi 8153* | A one-to-one mapping induces a one-to-one mapping on finite subsets. (Contributed by Mario Carneiro, 25-Jan-2015.) |
⊢ (𝐹:𝐴–1-1-onto→𝐵 → (𝑏 ∈ (𝒫 𝐴 ∩ Fin) ↦ (𝐹 “ 𝑏)):(𝒫 𝐴 ∩ Fin)–1-1-onto→(𝒫 𝐵 ∩ Fin)) | ||
Theorem | fissuni 8154* | A finite subset of a union is covered by finitely many elements. (Contributed by Stefan O'Rear, 2-Apr-2015.) |
⊢ ((𝐴 ⊆ ∪ 𝐵 ∧ 𝐴 ∈ Fin) → ∃𝑐 ∈ (𝒫 𝐵 ∩ Fin)𝐴 ⊆ ∪ 𝑐) | ||
Theorem | fipreima 8155* | Given a finite subset 𝐴 of the range of a function, there exists a finite subset of the domain whose image is 𝐴. (Contributed by Jeff Madsen, 2-Sep-2009.) (Revised by Stefan O'Rear, 22-Feb-2015.) |
⊢ ((𝐹 Fn 𝐵 ∧ 𝐴 ⊆ ran 𝐹 ∧ 𝐴 ∈ Fin) → ∃𝑐 ∈ (𝒫 𝐵 ∩ Fin)(𝐹 “ 𝑐) = 𝐴) | ||
Theorem | finsschain 8156* | A finite subset of the union of a superset chain is a subset of some element of the chain. A useful preliminary result for alexsub 21659 and others. (Contributed by Jeff Hankins, 25-Jan-2010.) (Proof shortened by Mario Carneiro, 11-Feb-2015.) (Revised by Mario Carneiro, 18-May-2015.) |
⊢ (((𝐴 ≠ ∅ ∧ [⊊] Or 𝐴) ∧ (𝐵 ∈ Fin ∧ 𝐵 ⊆ ∪ 𝐴)) → ∃𝑧 ∈ 𝐴 𝐵 ⊆ 𝑧) | ||
Theorem | indexfi 8157* | If for every element of a finite indexing set 𝐴 there exists a corresponding element of another set 𝐵, then there exists a finite subset of 𝐵 consisting only of those elements which are indexed by 𝐴. Proven without the Axiom of Choice, unlike indexdom 32699. (Contributed by Jeff Madsen, 2-Sep-2009.) (Proof shortened by Mario Carneiro, 12-Sep-2015.) |
⊢ ((𝐴 ∈ Fin ∧ 𝐵 ∈ 𝑀 ∧ ∀𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜑) → ∃𝑐 ∈ Fin (𝑐 ⊆ 𝐵 ∧ ∀𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝑐 𝜑 ∧ ∀𝑦 ∈ 𝑐 ∃𝑥 ∈ 𝐴 𝜑)) | ||
Syntax | cfsupp 8158 | Extend class definition to include the predicate to be a finitely supported function. |
class finSupp | ||
Definition | df-fsupp 8159* | Define the property of a function to be finitely supported (in relation to a given zero). (Contributed by AV, 23-May-2019.) |
⊢ finSupp = {〈𝑟, 𝑧〉 ∣ (Fun 𝑟 ∧ (𝑟 supp 𝑧) ∈ Fin)} | ||
Theorem | relfsupp 8160 | The property of a function to be finitely supported is a relation. (Contributed by AV, 7-Jun-2019.) |
⊢ Rel finSupp | ||
Theorem | relprcnfsupp 8161 | A proper class is never finitely supported. (Contributed by AV, 7-Jun-2019.) |
⊢ (¬ 𝐴 ∈ V → ¬ 𝐴 finSupp 𝑍) | ||
Theorem | isfsupp 8162 | The property of a class to be a finitely supported function (in relation to a given zero). (Contributed by AV, 23-May-2019.) |
⊢ ((𝑅 ∈ 𝑉 ∧ 𝑍 ∈ 𝑊) → (𝑅 finSupp 𝑍 ↔ (Fun 𝑅 ∧ (𝑅 supp 𝑍) ∈ Fin))) | ||
Theorem | funisfsupp 8163 | The property of a function to be finitely supported (in relation to a given zero). (Contributed by AV, 23-May-2019.) |
⊢ ((Fun 𝑅 ∧ 𝑅 ∈ 𝑉 ∧ 𝑍 ∈ 𝑊) → (𝑅 finSupp 𝑍 ↔ (𝑅 supp 𝑍) ∈ Fin)) | ||
Theorem | fsuppimp 8164 | Implications of a class being a finitely supported function (in relation to a given zero). (Contributed by AV, 26-May-2019.) |
⊢ (𝑅 finSupp 𝑍 → (Fun 𝑅 ∧ (𝑅 supp 𝑍) ∈ Fin)) | ||
Theorem | fsuppimpd 8165 | A finitely supported function is a function with a finite support. (Contributed by AV, 6-Jun-2019.) |
⊢ (𝜑 → 𝐹 finSupp 𝑍) ⇒ ⊢ (𝜑 → (𝐹 supp 𝑍) ∈ Fin) | ||
Theorem | fisuppfi 8166 | A function on a finite set is finitely supported. (Contributed by Mario Carneiro, 20-Jun-2015.) |
⊢ (𝜑 → 𝐴 ∈ Fin) & ⊢ (𝜑 → 𝐹:𝐴⟶𝐵) ⇒ ⊢ (𝜑 → (◡𝐹 “ 𝐶) ∈ Fin) | ||
Theorem | fdmfisuppfi 8167 | The support of a function with a finite domain is always finite. (Contributed by AV, 27-Apr-2019.) |
⊢ (𝜑 → 𝐹:𝐷⟶𝑅) & ⊢ (𝜑 → 𝐷 ∈ Fin) & ⊢ (𝜑 → 𝑍 ∈ 𝑉) ⇒ ⊢ (𝜑 → (𝐹 supp 𝑍) ∈ Fin) | ||
Theorem | fdmfifsupp 8168 | A function with a finite domain is always finitely supported. (Contributed by AV, 25-May-2019.) |
⊢ (𝜑 → 𝐹:𝐷⟶𝑅) & ⊢ (𝜑 → 𝐷 ∈ Fin) & ⊢ (𝜑 → 𝑍 ∈ 𝑉) ⇒ ⊢ (𝜑 → 𝐹 finSupp 𝑍) | ||
Theorem | fsuppmptdm 8169* | A mapping with a finite domain is finitely supported. (Contributed by AV, 7-Jun-2019.) |
⊢ 𝐹 = (𝑥 ∈ 𝐴 ↦ 𝑌) & ⊢ (𝜑 → 𝐴 ∈ Fin) & ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → 𝑌 ∈ 𝑉) & ⊢ (𝜑 → 𝑍 ∈ 𝑊) ⇒ ⊢ (𝜑 → 𝐹 finSupp 𝑍) | ||
Theorem | fndmfisuppfi 8170 | The support of a function with a finite domain is always finite. (Contributed by AV, 25-May-2019.) |
⊢ (𝜑 → 𝐹 Fn 𝐷) & ⊢ (𝜑 → 𝐷 ∈ Fin) & ⊢ (𝜑 → 𝑍 ∈ 𝑉) ⇒ ⊢ (𝜑 → (𝐹 supp 𝑍) ∈ Fin) | ||
Theorem | fndmfifsupp 8171 | A function with a finite domain is always finitely supported. (Contributed by AV, 25-May-2019.) |
⊢ (𝜑 → 𝐹 Fn 𝐷) & ⊢ (𝜑 → 𝐷 ∈ Fin) & ⊢ (𝜑 → 𝑍 ∈ 𝑉) ⇒ ⊢ (𝜑 → 𝐹 finSupp 𝑍) | ||
Theorem | suppeqfsuppbi 8172 | If two functions have the same support, one function is finitely supported iff the other one is finitely supported. (Contributed by AV, 30-Jun-2019.) |
⊢ (((𝐹 ∈ 𝑈 ∧ Fun 𝐹) ∧ (𝐺 ∈ 𝑉 ∧ Fun 𝐺)) → ((𝐹 supp 𝑍) = (𝐺 supp 𝑍) → (𝐹 finSupp 𝑍 ↔ 𝐺 finSupp 𝑍))) | ||
Theorem | suppssfifsupp 8173 | If the support of a function is a subset of a finite set, the function is finitely supported. (Contributed by AV, 15-Jul-2019.) |
⊢ (((𝐺 ∈ 𝑉 ∧ Fun 𝐺 ∧ 𝑍 ∈ 𝑊) ∧ (𝐹 ∈ Fin ∧ (𝐺 supp 𝑍) ⊆ 𝐹)) → 𝐺 finSupp 𝑍) | ||
Theorem | fsuppsssupp 8174 | If the support of a function is a subset of the support of a finitely supported function, the function is finitely supported. (Contributed by AV, 2-Jul-2019.) (Proof shortened by AV, 15-Jul-2019.) |
⊢ (((𝐺 ∈ 𝑉 ∧ Fun 𝐺) ∧ (𝐹 finSupp 𝑍 ∧ (𝐺 supp 𝑍) ⊆ (𝐹 supp 𝑍))) → 𝐺 finSupp 𝑍) | ||
Theorem | fsuppxpfi 8175 | The cartesian product of two finitely supported functions is finite. (Contributed by AV, 17-Jul-2019.) |
⊢ ((𝐹 finSupp 𝑍 ∧ 𝐺 finSupp 𝑍) → ((𝐹 supp 𝑍) × (𝐺 supp 𝑍)) ∈ Fin) | ||
Theorem | fczfsuppd 8176 | A constant function with value zero is finitely supported. (Contributed by AV, 30-Jun-2019.) |
⊢ (𝜑 → 𝐵 ∈ 𝑉) & ⊢ (𝜑 → 𝑍 ∈ 𝑊) ⇒ ⊢ (𝜑 → (𝐵 × {𝑍}) finSupp 𝑍) | ||
Theorem | fsuppun 8177 | The union of two finitely supported functions is finitely supported (but not necessarily a function!). (Contributed by AV, 3-Jun-2019.) |
⊢ (𝜑 → 𝐹 finSupp 𝑍) & ⊢ (𝜑 → 𝐺 finSupp 𝑍) ⇒ ⊢ (𝜑 → ((𝐹 ∪ 𝐺) supp 𝑍) ∈ Fin) | ||
Theorem | fsuppunfi 8178 | The union of the support of two finitely supported functions is finite. (Contributed by AV, 1-Jul-2019.) |
⊢ (𝜑 → 𝐹 finSupp 𝑍) & ⊢ (𝜑 → 𝐺 finSupp 𝑍) ⇒ ⊢ (𝜑 → ((𝐹 supp 𝑍) ∪ (𝐺 supp 𝑍)) ∈ Fin) | ||
Theorem | fsuppunbi 8179 | If the union of two classes/functions is a function, this union is finitely supported iff the two functions are finitely supported. (Contributed by AV, 18-Jun-2019.) |
⊢ (𝜑 → Fun (𝐹 ∪ 𝐺)) ⇒ ⊢ (𝜑 → ((𝐹 ∪ 𝐺) finSupp 𝑍 ↔ (𝐹 finSupp 𝑍 ∧ 𝐺 finSupp 𝑍))) | ||
Theorem | 0fsupp 8180 | The empty set is a finitely supported function. (Contributed by AV, 19-Jul-2019.) |
⊢ (𝑍 ∈ 𝑉 → ∅ finSupp 𝑍) | ||
Theorem | snopfsupp 8181 | A singleton containing an ordered pair is a finitely supported function. (Contributed by AV, 19-Jul-2019.) |
⊢ ((𝑋 ∈ 𝑉 ∧ 𝑌 ∈ 𝑊 ∧ 𝑍 ∈ 𝑈) → {〈𝑋, 𝑌〉} finSupp 𝑍) | ||
Theorem | funsnfsupp 8182 | Finite support for a function extended by a singleton. (Contributed by Stefan O'Rear, 27-Feb-2015.) (Revised by AV, 19-Jul-2019.) |
⊢ (((𝑋 ∈ 𝑉 ∧ 𝑌 ∈ 𝑊) ∧ (Fun 𝐹 ∧ 𝑋 ∉ dom 𝐹)) → ((𝐹 ∪ {〈𝑋, 𝑌〉}) finSupp 𝑍 ↔ 𝐹 finSupp 𝑍)) | ||
Theorem | fsuppres 8183 | The restriction of a finitely supported function is finitely supported. (Contributed by AV, 14-Jul-2019.) |
⊢ (𝜑 → 𝐹 finSupp 𝑍) & ⊢ (𝜑 → 𝑍 ∈ 𝑉) ⇒ ⊢ (𝜑 → (𝐹 ↾ 𝑋) finSupp 𝑍) | ||
Theorem | ressuppfi 8184 | If the support of the restriction of a function by a set which, subtracted from the domain of the function so that its difference is finite, the support of the function itself is finite. (Contributed by AV, 22-Apr-2019.) |
⊢ (𝜑 → (dom 𝐹 ∖ 𝐵) ∈ Fin) & ⊢ (𝜑 → 𝐹 ∈ 𝑊) & ⊢ (𝜑 → 𝐺 = (𝐹 ↾ 𝐵)) & ⊢ (𝜑 → (𝐺 supp 𝑍) ∈ Fin) & ⊢ (𝜑 → 𝑍 ∈ 𝑉) ⇒ ⊢ (𝜑 → (𝐹 supp 𝑍) ∈ Fin) | ||
Theorem | resfsupp 8185 | If the restriction of a function by a set which, subtracted from the domain of the function so that its difference is finitely supported, the function itself is finitely supported. (Contributed by AV, 27-May-2019.) |
⊢ (𝜑 → (dom 𝐹 ∖ 𝐵) ∈ Fin) & ⊢ (𝜑 → 𝐹 ∈ 𝑊) & ⊢ (𝜑 → Fun 𝐹) & ⊢ (𝜑 → 𝐺 = (𝐹 ↾ 𝐵)) & ⊢ (𝜑 → 𝐺 finSupp 𝑍) & ⊢ (𝜑 → 𝑍 ∈ 𝑉) ⇒ ⊢ (𝜑 → 𝐹 finSupp 𝑍) | ||
Theorem | resfifsupp 8186 | The restriction of a function to a finite set is finitely supported. (Contributed by AV, 12-Dec-2019.) |
⊢ (𝜑 → Fun 𝐹) & ⊢ (𝜑 → 𝑋 ∈ Fin) & ⊢ (𝜑 → 𝑍 ∈ 𝑉) ⇒ ⊢ (𝜑 → (𝐹 ↾ 𝑋) finSupp 𝑍) | ||
Theorem | frnfsuppbi 8187 | Two ways of saying that a function with known codomain is finitely supported. (Contributed by AV, 8-Jul-2019.) |
⊢ ((𝐼 ∈ 𝑉 ∧ 𝑍 ∈ 𝑊) → (𝐹:𝐼⟶𝑆 → (𝐹 finSupp 𝑍 ↔ (◡𝐹 “ (𝑆 ∖ {𝑍})) ∈ Fin))) | ||
Theorem | fsuppmptif 8188* | A function mapping an argument to either a value of a finitely supported function or zero is finitely supported. (Contributed by AV, 6-Jun-2019.) |
⊢ (𝜑 → 𝐹:𝐴⟶𝐵) & ⊢ (𝜑 → 𝐴 ∈ 𝑉) & ⊢ (𝜑 → 𝑍 ∈ 𝑊) & ⊢ (𝜑 → 𝐹 finSupp 𝑍) ⇒ ⊢ (𝜑 → (𝑘 ∈ 𝐴 ↦ if(𝑘 ∈ 𝐷, (𝐹‘𝑘), 𝑍)) finSupp 𝑍) | ||
Theorem | fsuppcolem 8189 | Lemma for fsuppco 8190. Formula building theorem for finite supports: rearranging the index set. (Contributed by Stefan O'Rear, 21-Mar-2015.) |
⊢ (𝜑 → (◡𝐹 “ (V ∖ {𝑍})) ∈ Fin) & ⊢ (𝜑 → 𝐺:𝑋–1-1→𝑌) ⇒ ⊢ (𝜑 → (◡(𝐹 ∘ 𝐺) “ (V ∖ {𝑍})) ∈ Fin) | ||
Theorem | fsuppco 8190 | The composition of a 1-1 function with a finitely supported function is finitely supported. (Contributed by AV, 28-May-2019.) |
⊢ (𝜑 → 𝐹 finSupp 𝑍) & ⊢ (𝜑 → 𝐺:𝑋–1-1→𝑌) & ⊢ (𝜑 → 𝑍 ∈ 𝑊) & ⊢ (𝜑 → 𝐹 ∈ 𝑉) ⇒ ⊢ (𝜑 → (𝐹 ∘ 𝐺) finSupp 𝑍) | ||
Theorem | fsuppco2 8191 | The composition of a function which maps the zero to zero with a finitely supported function is finitely supported. This is not only a special case of fsuppcor 8192 because it does not require that the "zero" is an element of the range of the finitely supported function. (Contributed by AV, 6-Jun-2019.) |
⊢ (𝜑 → 𝑍 ∈ 𝑊) & ⊢ (𝜑 → 𝐹:𝐴⟶𝐵) & ⊢ (𝜑 → 𝐺:𝐵⟶𝐵) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) & ⊢ (𝜑 → 𝐵 ∈ 𝑉) & ⊢ (𝜑 → 𝐹 finSupp 𝑍) & ⊢ (𝜑 → (𝐺‘𝑍) = 𝑍) ⇒ ⊢ (𝜑 → (𝐺 ∘ 𝐹) finSupp 𝑍) | ||
Theorem | fsuppcor 8192 | The composition of a function which maps the zero of the range of a finitely supported function to the zero of its range with this finitely supported function is finitely supported. (Contributed by AV, 6-Jun-2019.) |
⊢ (𝜑 → 0 ∈ 𝑊) & ⊢ (𝜑 → 𝑍 ∈ 𝐵) & ⊢ (𝜑 → 𝐹:𝐴⟶𝐶) & ⊢ (𝜑 → 𝐺:𝐵⟶𝐷) & ⊢ (𝜑 → 𝐶 ⊆ 𝐵) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) & ⊢ (𝜑 → 𝐵 ∈ 𝑉) & ⊢ (𝜑 → 𝐹 finSupp 𝑍) & ⊢ (𝜑 → (𝐺‘𝑍) = 0 ) ⇒ ⊢ (𝜑 → (𝐺 ∘ 𝐹) finSupp 0 ) | ||
Theorem | mapfienlem1 8193* | Lemma 1 for mapfien 8196. (Contributed by AV, 3-Jul-2019.) |
⊢ 𝑆 = {𝑥 ∈ (𝐵 ↑𝑚 𝐴) ∣ 𝑥 finSupp 𝑍} & ⊢ 𝑇 = {𝑥 ∈ (𝐷 ↑𝑚 𝐶) ∣ 𝑥 finSupp 𝑊} & ⊢ 𝑊 = (𝐺‘𝑍) & ⊢ (𝜑 → 𝐹:𝐶–1-1-onto→𝐴) & ⊢ (𝜑 → 𝐺:𝐵–1-1-onto→𝐷) & ⊢ (𝜑 → 𝐴 ∈ V) & ⊢ (𝜑 → 𝐵 ∈ V) & ⊢ (𝜑 → 𝐶 ∈ V) & ⊢ (𝜑 → 𝐷 ∈ V) & ⊢ (𝜑 → 𝑍 ∈ 𝐵) ⇒ ⊢ ((𝜑 ∧ 𝑓 ∈ 𝑆) → (𝐺 ∘ (𝑓 ∘ 𝐹)) finSupp 𝑊) | ||
Theorem | mapfienlem2 8194* | Lemma 2 for mapfien 8196. (Contributed by AV, 3-Jul-2019.) |
⊢ 𝑆 = {𝑥 ∈ (𝐵 ↑𝑚 𝐴) ∣ 𝑥 finSupp 𝑍} & ⊢ 𝑇 = {𝑥 ∈ (𝐷 ↑𝑚 𝐶) ∣ 𝑥 finSupp 𝑊} & ⊢ 𝑊 = (𝐺‘𝑍) & ⊢ (𝜑 → 𝐹:𝐶–1-1-onto→𝐴) & ⊢ (𝜑 → 𝐺:𝐵–1-1-onto→𝐷) & ⊢ (𝜑 → 𝐴 ∈ V) & ⊢ (𝜑 → 𝐵 ∈ V) & ⊢ (𝜑 → 𝐶 ∈ V) & ⊢ (𝜑 → 𝐷 ∈ V) & ⊢ (𝜑 → 𝑍 ∈ 𝐵) ⇒ ⊢ ((𝜑 ∧ 𝑔 ∈ 𝑇) → ((◡𝐺 ∘ 𝑔) ∘ ◡𝐹) finSupp 𝑍) | ||
Theorem | mapfienlem3 8195* | Lemma 3 for mapfien 8196. (Contributed by AV, 3-Jul-2019.) |
⊢ 𝑆 = {𝑥 ∈ (𝐵 ↑𝑚 𝐴) ∣ 𝑥 finSupp 𝑍} & ⊢ 𝑇 = {𝑥 ∈ (𝐷 ↑𝑚 𝐶) ∣ 𝑥 finSupp 𝑊} & ⊢ 𝑊 = (𝐺‘𝑍) & ⊢ (𝜑 → 𝐹:𝐶–1-1-onto→𝐴) & ⊢ (𝜑 → 𝐺:𝐵–1-1-onto→𝐷) & ⊢ (𝜑 → 𝐴 ∈ V) & ⊢ (𝜑 → 𝐵 ∈ V) & ⊢ (𝜑 → 𝐶 ∈ V) & ⊢ (𝜑 → 𝐷 ∈ V) & ⊢ (𝜑 → 𝑍 ∈ 𝐵) ⇒ ⊢ ((𝜑 ∧ 𝑔 ∈ 𝑇) → ((◡𝐺 ∘ 𝑔) ∘ ◡𝐹) ∈ 𝑆) | ||
Theorem | mapfien 8196* | A bijection of the base sets induces a bijection on the set of finitely supported functions. (Contributed by Mario Carneiro, 30-May-2015.) (Revised by AV, 3-Jul-2019.) |
⊢ 𝑆 = {𝑥 ∈ (𝐵 ↑𝑚 𝐴) ∣ 𝑥 finSupp 𝑍} & ⊢ 𝑇 = {𝑥 ∈ (𝐷 ↑𝑚 𝐶) ∣ 𝑥 finSupp 𝑊} & ⊢ 𝑊 = (𝐺‘𝑍) & ⊢ (𝜑 → 𝐹:𝐶–1-1-onto→𝐴) & ⊢ (𝜑 → 𝐺:𝐵–1-1-onto→𝐷) & ⊢ (𝜑 → 𝐴 ∈ V) & ⊢ (𝜑 → 𝐵 ∈ V) & ⊢ (𝜑 → 𝐶 ∈ V) & ⊢ (𝜑 → 𝐷 ∈ V) & ⊢ (𝜑 → 𝑍 ∈ 𝐵) ⇒ ⊢ (𝜑 → (𝑓 ∈ 𝑆 ↦ (𝐺 ∘ (𝑓 ∘ 𝐹))):𝑆–1-1-onto→𝑇) | ||
Theorem | mapfien2 8197* | Equinumerousity relation for sets of finitely supported functions. (Contributed by Stefan O'Rear, 9-Jul-2015.) (Revised by AV, 7-Jul-2019.) |
⊢ 𝑆 = {𝑥 ∈ (𝐵 ↑𝑚 𝐴) ∣ 𝑥 finSupp 0 } & ⊢ 𝑇 = {𝑥 ∈ (𝐷 ↑𝑚 𝐶) ∣ 𝑥 finSupp 𝑊} & ⊢ (𝜑 → 𝐴 ≈ 𝐶) & ⊢ (𝜑 → 𝐵 ≈ 𝐷) & ⊢ (𝜑 → 0 ∈ 𝐵) & ⊢ (𝜑 → 𝑊 ∈ 𝐷) ⇒ ⊢ (𝜑 → 𝑆 ≈ 𝑇) | ||
Theorem | sniffsupp 8198* | A function mapping all but one arguments to zero is finitely supported. (Contributed by AV, 8-Jul-2019.) |
⊢ (𝜑 → 𝐼 ∈ 𝑉) & ⊢ (𝜑 → 0 ∈ 𝑊) & ⊢ 𝐹 = (𝑥 ∈ 𝐼 ↦ if(𝑥 = 𝑋, 𝐴, 0 )) ⇒ ⊢ (𝜑 → 𝐹 finSupp 0 ) | ||
Syntax | cfi 8199 | Extend class notation with the function whose value is the class of all the finite intersections of the elements of a given set. |
class fi | ||
Definition | df-fi 8200* | Function whose value is the class of all the finite intersections of the elements of 𝑥. (Contributed by FL, 27-Apr-2008.) |
⊢ fi = (𝑥 ∈ V ↦ {𝑧 ∣ ∃𝑦 ∈ (𝒫 𝑥 ∩ Fin)𝑧 = ∩ 𝑦}) |
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