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Type | Label | Description |
---|---|---|
Statement | ||
Theorem | brcodir 6001* | Two ways of saying that two elements have an upper bound. (Contributed by Mario Carneiro, 3-Nov-2015.) |
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → (𝐴(◡𝑅 ∘ 𝑅)𝐵 ↔ ∃𝑧(𝐴𝑅𝑧 ∧ 𝐵𝑅𝑧))) | ||
Theorem | codir 6002* | Two ways of saying a relation is directed. (Contributed by Mario Carneiro, 22-Nov-2013.) |
⊢ ((𝐴 × 𝐵) ⊆ (◡𝑅 ∘ 𝑅) ↔ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 ∃𝑧(𝑥𝑅𝑧 ∧ 𝑦𝑅𝑧)) | ||
Theorem | qfto 6003* | A quantifier-free way of expressing the total order predicate. (Contributed by Mario Carneiro, 22-Nov-2013.) |
⊢ ((𝐴 × 𝐵) ⊆ (𝑅 ∪ ◡𝑅) ↔ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 (𝑥𝑅𝑦 ∨ 𝑦𝑅𝑥)) | ||
Theorem | xpidtr 6004 | A Cartesian square is a transitive relation. (Contributed by FL, 31-Jul-2009.) |
⊢ ((𝐴 × 𝐴) ∘ (𝐴 × 𝐴)) ⊆ (𝐴 × 𝐴) | ||
Theorem | trin2 6005 | The intersection of two transitive classes is transitive. (Contributed by FL, 31-Jul-2009.) |
⊢ (((𝑅 ∘ 𝑅) ⊆ 𝑅 ∧ (𝑆 ∘ 𝑆) ⊆ 𝑆) → ((𝑅 ∩ 𝑆) ∘ (𝑅 ∩ 𝑆)) ⊆ (𝑅 ∩ 𝑆)) | ||
Theorem | poirr2 6006 | A partial order is irreflexive. (Contributed by Mario Carneiro, 2-Nov-2015.) (Proof shortened by Peter Mazsa, 2-Oct-2022.) |
⊢ (𝑅 Po 𝐴 → (𝑅 ∩ ( I ↾ 𝐴)) = ∅) | ||
Theorem | trinxp 6007 | The relation induced by a transitive relation on a part of its field is transitive. (Taking the intersection of a relation with a Cartesian square is a way to restrict it to a subset of its field.) (Contributed by FL, 31-Jul-2009.) |
⊢ ((𝑅 ∘ 𝑅) ⊆ 𝑅 → ((𝑅 ∩ (𝐴 × 𝐴)) ∘ (𝑅 ∩ (𝐴 × 𝐴))) ⊆ (𝑅 ∩ (𝐴 × 𝐴))) | ||
Theorem | soirri 6008 | A strict order relation is irreflexive. (Contributed by NM, 10-Feb-1996.) (Revised by Mario Carneiro, 10-May-2013.) |
⊢ 𝑅 Or 𝑆 & ⊢ 𝑅 ⊆ (𝑆 × 𝑆) ⇒ ⊢ ¬ 𝐴𝑅𝐴 | ||
Theorem | sotri 6009 | A strict order relation is a transitive relation. (Contributed by NM, 10-Feb-1996.) (Revised by Mario Carneiro, 10-May-2013.) |
⊢ 𝑅 Or 𝑆 & ⊢ 𝑅 ⊆ (𝑆 × 𝑆) ⇒ ⊢ ((𝐴𝑅𝐵 ∧ 𝐵𝑅𝐶) → 𝐴𝑅𝐶) | ||
Theorem | son2lpi 6010 | A strict order relation has no 2-cycle loops. (Contributed by NM, 10-Feb-1996.) (Revised by Mario Carneiro, 10-May-2013.) |
⊢ 𝑅 Or 𝑆 & ⊢ 𝑅 ⊆ (𝑆 × 𝑆) ⇒ ⊢ ¬ (𝐴𝑅𝐵 ∧ 𝐵𝑅𝐴) | ||
Theorem | sotri2 6011 | A transitivity relation. (Read 𝐴 ≤ 𝐵 and 𝐵 < 𝐶 implies 𝐴 < 𝐶.) (Contributed by Mario Carneiro, 10-May-2013.) |
⊢ 𝑅 Or 𝑆 & ⊢ 𝑅 ⊆ (𝑆 × 𝑆) ⇒ ⊢ ((𝐴 ∈ 𝑆 ∧ ¬ 𝐵𝑅𝐴 ∧ 𝐵𝑅𝐶) → 𝐴𝑅𝐶) | ||
Theorem | sotri3 6012 | A transitivity relation. (Read 𝐴 < 𝐵 and 𝐵 ≤ 𝐶 implies 𝐴 < 𝐶.) (Contributed by Mario Carneiro, 10-May-2013.) |
⊢ 𝑅 Or 𝑆 & ⊢ 𝑅 ⊆ (𝑆 × 𝑆) ⇒ ⊢ ((𝐶 ∈ 𝑆 ∧ 𝐴𝑅𝐵 ∧ ¬ 𝐶𝑅𝐵) → 𝐴𝑅𝐶) | ||
Theorem | poleloe 6013 | Express "less than or equals" for general strict orders. (Contributed by Stefan O'Rear, 17-Jan-2015.) |
⊢ (𝐵 ∈ 𝑉 → (𝐴(𝑅 ∪ I )𝐵 ↔ (𝐴𝑅𝐵 ∨ 𝐴 = 𝐵))) | ||
Theorem | poltletr 6014 | Transitive law for general strict orders. (Contributed by Stefan O'Rear, 17-Jan-2015.) |
⊢ ((𝑅 Po 𝑋 ∧ (𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋 ∧ 𝐶 ∈ 𝑋)) → ((𝐴𝑅𝐵 ∧ 𝐵(𝑅 ∪ I )𝐶) → 𝐴𝑅𝐶)) | ||
Theorem | somin1 6015 | Property of a minimum in a strict order. (Contributed by Stefan O'Rear, 17-Jan-2015.) |
⊢ ((𝑅 Or 𝑋 ∧ (𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋)) → if(𝐴𝑅𝐵, 𝐴, 𝐵)(𝑅 ∪ I )𝐴) | ||
Theorem | somincom 6016 | Commutativity of minimum in a total order. (Contributed by Stefan O'Rear, 17-Jan-2015.) |
⊢ ((𝑅 Or 𝑋 ∧ (𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋)) → if(𝐴𝑅𝐵, 𝐴, 𝐵) = if(𝐵𝑅𝐴, 𝐵, 𝐴)) | ||
Theorem | somin2 6017 | Property of a minimum in a strict order. (Contributed by Stefan O'Rear, 17-Jan-2015.) |
⊢ ((𝑅 Or 𝑋 ∧ (𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋)) → if(𝐴𝑅𝐵, 𝐴, 𝐵)(𝑅 ∪ I )𝐵) | ||
Theorem | soltmin 6018 | Being less than a minimum, for a general total order. (Contributed by Stefan O'Rear, 17-Jan-2015.) |
⊢ ((𝑅 Or 𝑋 ∧ (𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋 ∧ 𝐶 ∈ 𝑋)) → (𝐴𝑅if(𝐵𝑅𝐶, 𝐵, 𝐶) ↔ (𝐴𝑅𝐵 ∧ 𝐴𝑅𝐶))) | ||
Theorem | cnvopab 6019* | The converse of a class abstraction of ordered pairs. (Contributed by NM, 11-Dec-2003.) (Proof shortened by Andrew Salmon, 27-Aug-2011.) |
⊢ ◡{〈𝑥, 𝑦〉 ∣ 𝜑} = {〈𝑦, 𝑥〉 ∣ 𝜑} | ||
Theorem | mptcnv 6020* | The converse of a mapping function. (Contributed by Thierry Arnoux, 16-Jan-2017.) |
⊢ (𝜑 → ((𝑥 ∈ 𝐴 ∧ 𝑦 = 𝐵) ↔ (𝑦 ∈ 𝐶 ∧ 𝑥 = 𝐷))) ⇒ ⊢ (𝜑 → ◡(𝑥 ∈ 𝐴 ↦ 𝐵) = (𝑦 ∈ 𝐶 ↦ 𝐷)) | ||
Theorem | cnv0 6021 | The converse of the empty set. (Contributed by NM, 6-Apr-1998.) Remove dependency on ax-sep 5208, ax-nul 5215, ax-pr 5338. (Revised by KP, 25-Oct-2021.) |
⊢ ◡∅ = ∅ | ||
Theorem | cnvi 6022 | The converse of the identity relation. Theorem 3.7(ii) of [Monk1] p. 36. (Contributed by NM, 26-Apr-1998.) (Proof shortened by Andrew Salmon, 27-Aug-2011.) |
⊢ ◡ I = I | ||
Theorem | cnvun 6023 | The converse of a union is the union of converses. Theorem 16 of [Suppes] p. 62. (Contributed by NM, 25-Mar-1998.) (Proof shortened by Andrew Salmon, 27-Aug-2011.) |
⊢ ◡(𝐴 ∪ 𝐵) = (◡𝐴 ∪ ◡𝐵) | ||
Theorem | cnvdif 6024 | Distributive law for converse over class difference. (Contributed by Mario Carneiro, 26-Jun-2014.) |
⊢ ◡(𝐴 ∖ 𝐵) = (◡𝐴 ∖ ◡𝐵) | ||
Theorem | cnvin 6025 | Distributive law for converse over intersection. Theorem 15 of [Suppes] p. 62. (Contributed by NM, 25-Mar-1998.) (Revised by Mario Carneiro, 26-Jun-2014.) |
⊢ ◡(𝐴 ∩ 𝐵) = (◡𝐴 ∩ ◡𝐵) | ||
Theorem | rnun 6026 | Distributive law for range over union. Theorem 8 of [Suppes] p. 60. (Contributed by NM, 24-Mar-1998.) |
⊢ ran (𝐴 ∪ 𝐵) = (ran 𝐴 ∪ ran 𝐵) | ||
Theorem | rnin 6027 | The range of an intersection belongs the intersection of ranges. Theorem 9 of [Suppes] p. 60. (Contributed by NM, 15-Sep-2004.) |
⊢ ran (𝐴 ∩ 𝐵) ⊆ (ran 𝐴 ∩ ran 𝐵) | ||
Theorem | rniun 6028 | The range of an indexed union. (Contributed by Mario Carneiro, 29-May-2015.) |
⊢ ran ∪ 𝑥 ∈ 𝐴 𝐵 = ∪ 𝑥 ∈ 𝐴 ran 𝐵 | ||
Theorem | rnuni 6029* | The range of a union. Part of Exercise 8 of [Enderton] p. 41. (Contributed by NM, 17-Mar-2004.) (Revised by Mario Carneiro, 29-May-2015.) |
⊢ ran ∪ 𝐴 = ∪ 𝑥 ∈ 𝐴 ran 𝑥 | ||
Theorem | imaundi 6030 | Distributive law for image over union. Theorem 35 of [Suppes] p. 65. (Contributed by NM, 30-Sep-2002.) |
⊢ (𝐴 “ (𝐵 ∪ 𝐶)) = ((𝐴 “ 𝐵) ∪ (𝐴 “ 𝐶)) | ||
Theorem | imaundir 6031 | The image of a union. (Contributed by Jeff Hoffman, 17-Feb-2008.) |
⊢ ((𝐴 ∪ 𝐵) “ 𝐶) = ((𝐴 “ 𝐶) ∪ (𝐵 “ 𝐶)) | ||
Theorem | cnvimassrndm 6032 | The preimage of a superset of the range of a class is the domain of the class. Generalization of cnvimarndm 5967 for subsets. (Contributed by AV, 18-Sep-2024.) |
⊢ (ran 𝐹 ⊆ 𝐴 → (◡𝐹 “ 𝐴) = dom 𝐹) | ||
Theorem | dminss 6033 | An upper bound for intersection with a domain. Theorem 40 of [Suppes] p. 66, who calls it "somewhat surprising". (Contributed by NM, 11-Aug-2004.) |
⊢ (dom 𝑅 ∩ 𝐴) ⊆ (◡𝑅 “ (𝑅 “ 𝐴)) | ||
Theorem | imainss 6034 | An upper bound for intersection with an image. Theorem 41 of [Suppes] p. 66. (Contributed by NM, 11-Aug-2004.) |
⊢ ((𝑅 “ 𝐴) ∩ 𝐵) ⊆ (𝑅 “ (𝐴 ∩ (◡𝑅 “ 𝐵))) | ||
Theorem | inimass 6035 | The image of an intersection. (Contributed by Thierry Arnoux, 16-Dec-2017.) |
⊢ ((𝐴 ∩ 𝐵) “ 𝐶) ⊆ ((𝐴 “ 𝐶) ∩ (𝐵 “ 𝐶)) | ||
Theorem | inimasn 6036 | The intersection of the image of singleton. (Contributed by Thierry Arnoux, 16-Dec-2017.) |
⊢ (𝐶 ∈ 𝑉 → ((𝐴 ∩ 𝐵) “ {𝐶}) = ((𝐴 “ {𝐶}) ∩ (𝐵 “ {𝐶}))) | ||
Theorem | cnvxp 6037 | The converse of a Cartesian product. Exercise 11 of [Suppes] p. 67. (Contributed by NM, 14-Aug-1999.) (Proof shortened by Andrew Salmon, 27-Aug-2011.) |
⊢ ◡(𝐴 × 𝐵) = (𝐵 × 𝐴) | ||
Theorem | xp0 6038 | The Cartesian product with the empty set is empty. Part of Theorem 3.13(ii) of [Monk1] p. 37. (Contributed by NM, 12-Apr-2004.) |
⊢ (𝐴 × ∅) = ∅ | ||
Theorem | xpnz 6039 | The Cartesian product of nonempty classes is nonempty. (Variation of a theorem contributed by Raph Levien, 30-Jun-2006.) (Contributed by NM, 30-Jun-2006.) |
⊢ ((𝐴 ≠ ∅ ∧ 𝐵 ≠ ∅) ↔ (𝐴 × 𝐵) ≠ ∅) | ||
Theorem | xpeq0 6040 | At least one member of an empty Cartesian product is empty. (Contributed by NM, 27-Aug-2006.) |
⊢ ((𝐴 × 𝐵) = ∅ ↔ (𝐴 = ∅ ∨ 𝐵 = ∅)) | ||
Theorem | xpdisj1 6041 | Cartesian products with disjoint sets are disjoint. (Contributed by NM, 13-Sep-2004.) |
⊢ ((𝐴 ∩ 𝐵) = ∅ → ((𝐴 × 𝐶) ∩ (𝐵 × 𝐷)) = ∅) | ||
Theorem | xpdisj2 6042 | Cartesian products with disjoint sets are disjoint. (Contributed by NM, 13-Sep-2004.) |
⊢ ((𝐴 ∩ 𝐵) = ∅ → ((𝐶 × 𝐴) ∩ (𝐷 × 𝐵)) = ∅) | ||
Theorem | xpsndisj 6043 | Cartesian products with two different singletons are disjoint. (Contributed by NM, 28-Jul-2004.) |
⊢ (𝐵 ≠ 𝐷 → ((𝐴 × {𝐵}) ∩ (𝐶 × {𝐷})) = ∅) | ||
Theorem | difxp 6044 | Difference of Cartesian products, expressed in terms of a union of Cartesian products of differences. (Contributed by Jeff Madsen, 2-Sep-2009.) (Revised by Mario Carneiro, 26-Jun-2014.) |
⊢ ((𝐶 × 𝐷) ∖ (𝐴 × 𝐵)) = (((𝐶 ∖ 𝐴) × 𝐷) ∪ (𝐶 × (𝐷 ∖ 𝐵))) | ||
Theorem | difxp1 6045 | Difference law for Cartesian product. (Contributed by Scott Fenton, 18-Feb-2013.) (Revised by Mario Carneiro, 26-Jun-2014.) |
⊢ ((𝐴 ∖ 𝐵) × 𝐶) = ((𝐴 × 𝐶) ∖ (𝐵 × 𝐶)) | ||
Theorem | difxp2 6046 | Difference law for Cartesian product. (Contributed by Scott Fenton, 18-Feb-2013.) (Revised by Mario Carneiro, 26-Jun-2014.) |
⊢ (𝐴 × (𝐵 ∖ 𝐶)) = ((𝐴 × 𝐵) ∖ (𝐴 × 𝐶)) | ||
Theorem | djudisj 6047* | Disjoint unions with disjoint index sets are disjoint. (Contributed by Stefan O'Rear, 21-Nov-2014.) |
⊢ ((𝐴 ∩ 𝐵) = ∅ → (∪ 𝑥 ∈ 𝐴 ({𝑥} × 𝐶) ∩ ∪ 𝑦 ∈ 𝐵 ({𝑦} × 𝐷)) = ∅) | ||
Theorem | xpdifid 6048* | The set of distinct couples in a Cartesian product. (Contributed by Thierry Arnoux, 25-May-2019.) |
⊢ ∪ 𝑥 ∈ 𝐴 ({𝑥} × (𝐵 ∖ {𝑥})) = ((𝐴 × 𝐵) ∖ I ) | ||
Theorem | resdisj 6049 | A double restriction to disjoint classes is the empty set. (Contributed by NM, 7-Oct-2004.) (Proof shortened by Andrew Salmon, 27-Aug-2011.) |
⊢ ((𝐴 ∩ 𝐵) = ∅ → ((𝐶 ↾ 𝐴) ↾ 𝐵) = ∅) | ||
Theorem | rnxp 6050 | The range of a Cartesian product. Part of Theorem 3.13(x) of [Monk1] p. 37. (Contributed by NM, 12-Apr-2004.) |
⊢ (𝐴 ≠ ∅ → ran (𝐴 × 𝐵) = 𝐵) | ||
Theorem | dmxpss 6051 | The domain of a Cartesian product is included in its first factor. (Contributed by NM, 19-Mar-2007.) |
⊢ dom (𝐴 × 𝐵) ⊆ 𝐴 | ||
Theorem | rnxpss 6052 | The range of a Cartesian product is included in its second factor. (Contributed by NM, 16-Jan-2006.) (Proof shortened by Andrew Salmon, 27-Aug-2011.) |
⊢ ran (𝐴 × 𝐵) ⊆ 𝐵 | ||
Theorem | rnxpid 6053 | The range of a Cartesian square. (Contributed by FL, 17-May-2010.) |
⊢ ran (𝐴 × 𝐴) = 𝐴 | ||
Theorem | ssxpb 6054 | A Cartesian product subclass relationship is equivalent to the conjunction of the analogous relationships for the factors. (Contributed by NM, 17-Dec-2008.) |
⊢ ((𝐴 × 𝐵) ≠ ∅ → ((𝐴 × 𝐵) ⊆ (𝐶 × 𝐷) ↔ (𝐴 ⊆ 𝐶 ∧ 𝐵 ⊆ 𝐷))) | ||
Theorem | xp11 6055 | The Cartesian product of nonempty classes is a one-to-one "function" of its two "arguments". In other words, two Cartesian products, at least one with nonempty factors, are equal if and only if their respective factors are equal. (Contributed by NM, 31-May-2008.) |
⊢ ((𝐴 ≠ ∅ ∧ 𝐵 ≠ ∅) → ((𝐴 × 𝐵) = (𝐶 × 𝐷) ↔ (𝐴 = 𝐶 ∧ 𝐵 = 𝐷))) | ||
Theorem | xpcan 6056 | Cancellation law for Cartesian product. (Contributed by NM, 30-Aug-2011.) |
⊢ (𝐶 ≠ ∅ → ((𝐶 × 𝐴) = (𝐶 × 𝐵) ↔ 𝐴 = 𝐵)) | ||
Theorem | xpcan2 6057 | Cancellation law for Cartesian product. (Contributed by NM, 30-Aug-2011.) |
⊢ (𝐶 ≠ ∅ → ((𝐴 × 𝐶) = (𝐵 × 𝐶) ↔ 𝐴 = 𝐵)) | ||
Theorem | ssrnres 6058 | Two ways to express surjectivity of a restricted and corestricted binary relation (intersection of a binary relation with a Cartesian product): the LHS expresses inclusion in the range of the restricted relation, while the RHS expresses equality with the range of the restricted and corestricted relation. (Contributed by NM, 16-Jan-2006.) (Proof shortened by Peter Mazsa, 2-Oct-2022.) |
⊢ (𝐵 ⊆ ran (𝐶 ↾ 𝐴) ↔ ran (𝐶 ∩ (𝐴 × 𝐵)) = 𝐵) | ||
Theorem | rninxp 6059* | Two ways to express surjectivity of a restricted and corestricted binary relation (intersection of a binary relation with a Cartesian product). (Contributed by NM, 17-Jan-2006.) (Proof shortened by Andrew Salmon, 27-Aug-2011.) |
⊢ (ran (𝐶 ∩ (𝐴 × 𝐵)) = 𝐵 ↔ ∀𝑦 ∈ 𝐵 ∃𝑥 ∈ 𝐴 𝑥𝐶𝑦) | ||
Theorem | dminxp 6060* | Two ways to express totality of a restricted and corestricted binary relation (intersection of a binary relation with a Cartesian product). (Contributed by NM, 17-Jan-2006.) |
⊢ (dom (𝐶 ∩ (𝐴 × 𝐵)) = 𝐴 ↔ ∀𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝑥𝐶𝑦) | ||
Theorem | imainrect 6061 | Image by a restricted and corestricted binary relation (intersection of a binary relation with a Cartesian product). (Contributed by Stefan O'Rear, 19-Feb-2015.) |
⊢ ((𝐺 ∩ (𝐴 × 𝐵)) “ 𝑌) = ((𝐺 “ (𝑌 ∩ 𝐴)) ∩ 𝐵) | ||
Theorem | xpima 6062 | Direct image by a Cartesian product. (Contributed by Thierry Arnoux, 4-Feb-2017.) |
⊢ ((𝐴 × 𝐵) “ 𝐶) = if((𝐴 ∩ 𝐶) = ∅, ∅, 𝐵) | ||
Theorem | xpima1 6063 | Direct image by a Cartesian product (case of empty intersection with the domain). (Contributed by Thierry Arnoux, 16-Dec-2017.) |
⊢ ((𝐴 ∩ 𝐶) = ∅ → ((𝐴 × 𝐵) “ 𝐶) = ∅) | ||
Theorem | xpima2 6064 | Direct image by a Cartesian product (case of nonempty intersection with the domain). (Contributed by Thierry Arnoux, 16-Dec-2017.) |
⊢ ((𝐴 ∩ 𝐶) ≠ ∅ → ((𝐴 × 𝐵) “ 𝐶) = 𝐵) | ||
Theorem | xpimasn 6065 | Direct image of a singleton by a Cartesian product. (Contributed by Thierry Arnoux, 14-Jan-2018.) (Proof shortened by BJ, 6-Apr-2019.) |
⊢ (𝑋 ∈ 𝐴 → ((𝐴 × 𝐵) “ {𝑋}) = 𝐵) | ||
Theorem | sossfld 6066 | The base set of a strict order is contained in the field of the relation, except possibly for one element (note that ∅ Or {𝐵}). (Contributed by Mario Carneiro, 27-Apr-2015.) |
⊢ ((𝑅 Or 𝐴 ∧ 𝐵 ∈ 𝐴) → (𝐴 ∖ {𝐵}) ⊆ (dom 𝑅 ∪ ran 𝑅)) | ||
Theorem | sofld 6067 | The base set of a nonempty strict order is the same as the field of the relation. (Contributed by Mario Carneiro, 15-May-2015.) |
⊢ ((𝑅 Or 𝐴 ∧ 𝑅 ⊆ (𝐴 × 𝐴) ∧ 𝑅 ≠ ∅) → 𝐴 = (dom 𝑅 ∪ ran 𝑅)) | ||
Theorem | cnvcnv3 6068* | The set of all ordered pairs in a class is the same as the double converse. (Contributed by Mario Carneiro, 16-Aug-2015.) |
⊢ ◡◡𝑅 = {〈𝑥, 𝑦〉 ∣ 𝑥𝑅𝑦} | ||
Theorem | dfrel2 6069 | Alternate definition of relation. Exercise 2 of [TakeutiZaring] p. 25. (Contributed by NM, 29-Dec-1996.) |
⊢ (Rel 𝑅 ↔ ◡◡𝑅 = 𝑅) | ||
Theorem | dfrel4v 6070* | A relation can be expressed as the set of ordered pairs in it. An analogue of dffn5 6792 for relations. (Contributed by Mario Carneiro, 16-Aug-2015.) |
⊢ (Rel 𝑅 ↔ 𝑅 = {〈𝑥, 𝑦〉 ∣ 𝑥𝑅𝑦}) | ||
Theorem | dfrel4 6071* | A relation can be expressed as the set of ordered pairs in it. An analogue of dffn5 6792 for relations. (Contributed by Mario Carneiro, 16-Aug-2015.) (Revised by Thierry Arnoux, 11-May-2017.) |
⊢ Ⅎ𝑥𝑅 & ⊢ Ⅎ𝑦𝑅 ⇒ ⊢ (Rel 𝑅 ↔ 𝑅 = {〈𝑥, 𝑦〉 ∣ 𝑥𝑅𝑦}) | ||
Theorem | cnvcnv 6072 | The double converse of a class strips out all elements that are not ordered pairs. (Contributed by NM, 8-Dec-2003.) (Proof shortened by BJ, 26-Nov-2021.) |
⊢ ◡◡𝐴 = (𝐴 ∩ (V × V)) | ||
Theorem | cnvcnv2 6073 | The double converse of a class equals its restriction to the universe. (Contributed by NM, 8-Oct-2007.) |
⊢ ◡◡𝐴 = (𝐴 ↾ V) | ||
Theorem | cnvcnvss 6074 | The double converse of a class is a subclass. Exercise 2 of [TakeutiZaring] p. 25. (Contributed by NM, 23-Jul-2004.) |
⊢ ◡◡𝐴 ⊆ 𝐴 | ||
Theorem | cnvrescnv 6075 | Two ways to express the corestriction of a class. (Contributed by BJ, 28-Dec-2023.) |
⊢ ◡(◡𝑅 ↾ 𝐵) = (𝑅 ∩ (V × 𝐵)) | ||
Theorem | cnveqb 6076 | Equality theorem for converse. (Contributed by FL, 19-Sep-2011.) |
⊢ ((Rel 𝐴 ∧ Rel 𝐵) → (𝐴 = 𝐵 ↔ ◡𝐴 = ◡𝐵)) | ||
Theorem | cnveq0 6077 | A relation empty iff its converse is empty. (Contributed by FL, 19-Sep-2011.) |
⊢ (Rel 𝐴 → (𝐴 = ∅ ↔ ◡𝐴 = ∅)) | ||
Theorem | dfrel3 6078 | Alternate definition of relation. (Contributed by NM, 14-May-2008.) |
⊢ (Rel 𝑅 ↔ (𝑅 ↾ V) = 𝑅) | ||
Theorem | elid 6079* | Characterization of the elements of the identity relation. TODO: reorder theorems to move this theorem and dfrel3 6078 after elrid 5930. (Contributed by BJ, 28-Aug-2022.) |
⊢ (𝐴 ∈ I ↔ ∃𝑥 𝐴 = 〈𝑥, 𝑥〉) | ||
Theorem | dmresv 6080 | The domain of a universal restriction. (Contributed by NM, 14-May-2008.) |
⊢ dom (𝐴 ↾ V) = dom 𝐴 | ||
Theorem | rnresv 6081 | The range of a universal restriction. (Contributed by NM, 14-May-2008.) |
⊢ ran (𝐴 ↾ V) = ran 𝐴 | ||
Theorem | dfrn4 6082 | Range defined in terms of image. (Contributed by NM, 14-May-2008.) |
⊢ ran 𝐴 = (𝐴 “ V) | ||
Theorem | csbrn 6083 | Distribute proper substitution through the range of a class. (Contributed by Alan Sare, 10-Nov-2012.) |
⊢ ⦋𝐴 / 𝑥⦌ran 𝐵 = ran ⦋𝐴 / 𝑥⦌𝐵 | ||
Theorem | rescnvcnv 6084 | The restriction of the double converse of a class. (Contributed by NM, 8-Apr-2007.) (Proof shortened by Andrew Salmon, 27-Aug-2011.) |
⊢ (◡◡𝐴 ↾ 𝐵) = (𝐴 ↾ 𝐵) | ||
Theorem | cnvcnvres 6085 | The double converse of the restriction of a class. (Contributed by NM, 3-Jun-2007.) |
⊢ ◡◡(𝐴 ↾ 𝐵) = (◡◡𝐴 ↾ 𝐵) | ||
Theorem | imacnvcnv 6086 | The image of the double converse of a class. (Contributed by NM, 8-Apr-2007.) |
⊢ (◡◡𝐴 “ 𝐵) = (𝐴 “ 𝐵) | ||
Theorem | dmsnn0 6087 | The domain of a singleton is nonzero iff the singleton argument is an ordered pair. (Contributed by NM, 14-Dec-2008.) (Proof shortened by Andrew Salmon, 27-Aug-2011.) |
⊢ (𝐴 ∈ (V × V) ↔ dom {𝐴} ≠ ∅) | ||
Theorem | rnsnn0 6088 | The range of a singleton is nonzero iff the singleton argument is an ordered pair. (Contributed by NM, 14-Dec-2008.) |
⊢ (𝐴 ∈ (V × V) ↔ ran {𝐴} ≠ ∅) | ||
Theorem | dmsn0 6089 | The domain of the singleton of the empty set is empty. (Contributed by NM, 30-Jan-2004.) |
⊢ dom {∅} = ∅ | ||
Theorem | cnvsn0 6090 | The converse of the singleton of the empty set is empty. (Contributed by Mario Carneiro, 30-Aug-2015.) |
⊢ ◡{∅} = ∅ | ||
Theorem | dmsn0el 6091 | The domain of a singleton is empty if the singleton's argument contains the empty set. (Contributed by NM, 15-Dec-2008.) |
⊢ (∅ ∈ 𝐴 → dom {𝐴} = ∅) | ||
Theorem | relsn2 6092 | A singleton is a relation iff it has a nonempty domain. (Contributed by NM, 25-Sep-2013.) Make hypothesis an antecedent. (Revised by BJ, 12-Feb-2022.) |
⊢ (𝐴 ∈ 𝑉 → (Rel {𝐴} ↔ dom {𝐴} ≠ ∅)) | ||
Theorem | dmsnopg 6093 | The domain of a singleton of an ordered pair is the singleton of the first member. (Contributed by Mario Carneiro, 26-Apr-2015.) |
⊢ (𝐵 ∈ 𝑉 → dom {〈𝐴, 𝐵〉} = {𝐴}) | ||
Theorem | dmsnopss 6094 | The domain of a singleton of an ordered pair is a subset of the singleton of the first member (with no sethood assumptions on 𝐵). (Contributed by Mario Carneiro, 30-Apr-2015.) |
⊢ dom {〈𝐴, 𝐵〉} ⊆ {𝐴} | ||
Theorem | dmpropg 6095 | The domain of an unordered pair of ordered pairs. (Contributed by Mario Carneiro, 26-Apr-2015.) |
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐷 ∈ 𝑊) → dom {〈𝐴, 𝐵〉, 〈𝐶, 𝐷〉} = {𝐴, 𝐶}) | ||
Theorem | dmsnop 6096 | The domain of a singleton of an ordered pair is the singleton of the first member. (Contributed by NM, 30-Jan-2004.) (Proof shortened by Andrew Salmon, 27-Aug-2011.) (Revised by Mario Carneiro, 26-Apr-2015.) |
⊢ 𝐵 ∈ V ⇒ ⊢ dom {〈𝐴, 𝐵〉} = {𝐴} | ||
Theorem | dmprop 6097 | The domain of an unordered pair of ordered pairs. (Contributed by NM, 13-Sep-2011.) |
⊢ 𝐵 ∈ V & ⊢ 𝐷 ∈ V ⇒ ⊢ dom {〈𝐴, 𝐵〉, 〈𝐶, 𝐷〉} = {𝐴, 𝐶} | ||
Theorem | dmtpop 6098 | The domain of an unordered triple of ordered pairs. (Contributed by NM, 14-Sep-2011.) |
⊢ 𝐵 ∈ V & ⊢ 𝐷 ∈ V & ⊢ 𝐹 ∈ V ⇒ ⊢ dom {〈𝐴, 𝐵〉, 〈𝐶, 𝐷〉, 〈𝐸, 𝐹〉} = {𝐴, 𝐶, 𝐸} | ||
Theorem | cnvcnvsn 6099 | Double converse of a singleton of an ordered pair. (Unlike cnvsn 6106, this does not need any sethood assumptions on 𝐴 and 𝐵.) (Contributed by Mario Carneiro, 26-Apr-2015.) |
⊢ ◡◡{〈𝐴, 𝐵〉} = ◡{〈𝐵, 𝐴〉} | ||
Theorem | dmsnsnsn 6100 | The domain of the singleton of the singleton of a singleton. (Contributed by NM, 15-Sep-2004.) (Revised by Mario Carneiro, 26-Apr-2015.) |
⊢ dom {{{𝐴}}} = {𝐴} |
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