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Type | Label | Description |
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Statement | ||
Theorem | rp-fakeimass 43501 | A special case where implication appears to conform to a mixed associative law. (Contributed by RP, 29-Feb-2020.) |
⊢ ((𝜑 ∨ 𝜒) ↔ (((𝜑 → 𝜓) → 𝜒) ↔ (𝜑 → (𝜓 → 𝜒)))) | ||
Theorem | rp-fakeanorass 43502 | A special case where a mixture of and and or appears to conform to a mixed associative law. (Contributed by RP, 26-Feb-2020.) |
⊢ ((𝜒 → 𝜑) ↔ (((𝜑 ∧ 𝜓) ∨ 𝜒) ↔ (𝜑 ∧ (𝜓 ∨ 𝜒)))) | ||
Theorem | rp-fakeoranass 43503 | A special case where a mixture of or and and appears to conform to a mixed associative law. (Contributed by RP, 29-Feb-2020.) |
⊢ ((𝜑 → 𝜒) ↔ (((𝜑 ∨ 𝜓) ∧ 𝜒) ↔ (𝜑 ∨ (𝜓 ∧ 𝜒)))) | ||
Theorem | rp-fakeinunass 43504 | A special case where a mixture of intersection and union appears to conform to a mixed associative law. (Contributed by RP, 26-Feb-2020.) |
⊢ (𝐶 ⊆ 𝐴 ↔ ((𝐴 ∩ 𝐵) ∪ 𝐶) = (𝐴 ∩ (𝐵 ∪ 𝐶))) | ||
Theorem | rp-fakeuninass 43505 | A special case where a mixture of union and intersection appears to conform to a mixed associative law. (Contributed by RP, 29-Feb-2020.) |
⊢ (𝐴 ⊆ 𝐶 ↔ ((𝐴 ∪ 𝐵) ∩ 𝐶) = (𝐴 ∪ (𝐵 ∩ 𝐶))) | ||
Membership in the class of finite sets can be expressed in many ways. | ||
Theorem | rp-isfinite5 43506* | A set is said to be finite if it can be put in one-to-one correspondence with all the natural numbers between 1 and some 𝑛 ∈ ℕ0. (Contributed by RP, 3-Mar-2020.) |
⊢ (𝐴 ∈ Fin ↔ ∃𝑛 ∈ ℕ0 (1...𝑛) ≈ 𝐴) | ||
Theorem | rp-isfinite6 43507* | A set is said to be finite if it is either empty or it can be put in one-to-one correspondence with all the natural numbers between 1 and some 𝑛 ∈ ℕ. (Contributed by RP, 10-Mar-2020.) |
⊢ (𝐴 ∈ Fin ↔ (𝐴 = ∅ ∨ ∃𝑛 ∈ ℕ (1...𝑛) ≈ 𝐴)) | ||
Theorem | intabssd 43508* | When for each element 𝑦 there is a subset 𝐴 which may substituted for 𝑥 such that 𝑦 satisfying 𝜒 implies 𝑥 satisfies 𝜓 then the intersection of all 𝑥 that satisfy 𝜓 is a subclass the intersection of all 𝑦 that satisfy 𝜒. (Contributed by RP, 17-Oct-2020.) |
⊢ (𝜑 → 𝐴 ∈ 𝑉) & ⊢ ((𝜑 ∧ 𝑥 = 𝐴) → (𝜒 → 𝜓)) & ⊢ (𝜑 → 𝐴 ⊆ 𝑦) ⇒ ⊢ (𝜑 → ∩ {𝑥 ∣ 𝜓} ⊆ ∩ {𝑦 ∣ 𝜒}) | ||
Theorem | eu0 43509* | There is only one empty set. (Contributed by RP, 1-Oct-2023.) |
⊢ (∀𝑥 ¬ 𝑥 ∈ ∅ ∧ ∃!𝑥∀𝑦 ¬ 𝑦 ∈ 𝑥) | ||
Theorem | epelon2 43510 | Over the ordinal numbers, one may define the relation 𝐴 E 𝐵 iff 𝐴 ∈ 𝐵 and one finds that, under this ordering, On is a well-ordered class, see epweon 7793. This is a weak form of epelg 5589 which only requires that we know 𝐵 to be a set. (Contributed by RP, 27-Sep-2023.) |
⊢ ((𝐴 ∈ On ∧ 𝐵 ∈ On) → (𝐴 E 𝐵 ↔ 𝐴 ∈ 𝐵)) | ||
Theorem | ontric3g 43511* | For all 𝑥, 𝑦 ∈ On, one and only one of the following hold: 𝑥 ∈ 𝑦, 𝑦 = 𝑥, or 𝑦 ∈ 𝑥. This is a transparent strict trichotomy. (Contributed by RP, 27-Sep-2023.) |
⊢ ∀𝑥 ∈ On ∀𝑦 ∈ On ((𝑥 ∈ 𝑦 ↔ ¬ (𝑦 = 𝑥 ∨ 𝑦 ∈ 𝑥)) ∧ (𝑦 = 𝑥 ↔ ¬ (𝑥 ∈ 𝑦 ∨ 𝑦 ∈ 𝑥)) ∧ (𝑦 ∈ 𝑥 ↔ ¬ (𝑥 ∈ 𝑦 ∨ 𝑦 = 𝑥))) | ||
Theorem | dfsucon 43512* | 𝐴 is called a successor ordinal if it is not a limit ordinal and not the empty set. (Contributed by RP, 11-Nov-2023.) |
⊢ ((Ord 𝐴 ∧ ¬ Lim 𝐴 ∧ 𝐴 ≠ ∅) ↔ ∃𝑥 ∈ On 𝐴 = suc 𝑥) | ||
Theorem | snen1g 43513 | A singleton is equinumerous to ordinal one iff its content is a set. (Contributed by RP, 8-Oct-2023.) |
⊢ ({𝐴} ≈ 1o ↔ 𝐴 ∈ V) | ||
Theorem | snen1el 43514 | A singleton is equinumerous to ordinal one if its content is an element of it. (Contributed by RP, 8-Oct-2023.) |
⊢ ({𝐴} ≈ 1o ↔ 𝐴 ∈ {𝐴}) | ||
Theorem | sn1dom 43515 | A singleton is dominated by ordinal one. (Contributed by RP, 29-Oct-2023.) |
⊢ {𝐴} ≼ 1o | ||
Theorem | pr2dom 43516 | An unordered pair is dominated by ordinal two. (Contributed by RP, 29-Oct-2023.) |
⊢ {𝐴, 𝐵} ≼ 2o | ||
Theorem | tr3dom 43517 | An unordered triple is dominated by ordinal three. (Contributed by RP, 29-Oct-2023.) |
⊢ {𝐴, 𝐵, 𝐶} ≼ 3o | ||
Theorem | ensucne0 43518 | A class equinumerous to a successor is never empty. (Contributed by RP, 11-Nov-2023.) (Proof shortened by SN, 16-Nov-2023.) |
⊢ (𝐴 ≈ suc 𝐵 → 𝐴 ≠ ∅) | ||
Theorem | ensucne0OLD 43519 | A class equinumerous to a successor is never empty. (Contributed by RP, 11-Nov-2023.) (Proof modification is discouraged.) (New usage is discouraged.) |
⊢ (𝐴 ≈ suc 𝐵 → 𝐴 ≠ ∅) | ||
Theorem | dfom6 43520 | Let ω be defined to be the union of the set of all finite ordinals. (Contributed by RP, 27-Sep-2023.) |
⊢ ω = ∪ (On ∩ Fin) | ||
Theorem | infordmin 43521 | ω is the smallest infinite ordinal. (Contributed by RP, 27-Sep-2023.) |
⊢ ∀𝑥 ∈ (On ∖ Fin)ω ⊆ 𝑥 | ||
Theorem | iscard4 43522 | Two ways to express the property of being a cardinal number. (Contributed by RP, 8-Nov-2023.) |
⊢ ((card‘𝐴) = 𝐴 ↔ 𝐴 ∈ ran card) | ||
Theorem | minregex 43523* | Given any cardinal number 𝐴, there exists an argument 𝑥, which yields the least regular uncountable value of ℵ which is greater to or equal to 𝐴. This proof uses AC. (Contributed by RP, 23-Nov-2023.) |
⊢ (𝐴 ∈ (ran card ∖ ω) → ∃𝑥 ∈ On 𝑥 = ∩ {𝑦 ∈ On ∣ (∅ ∈ 𝑦 ∧ 𝐴 ⊆ (ℵ‘𝑦) ∧ (cf‘(ℵ‘𝑦)) = (ℵ‘𝑦))}) | ||
Theorem | minregex2 43524* | Given any cardinal number 𝐴, there exists an argument 𝑥, which yields the least regular uncountable value of ℵ which dominates 𝐴. This proof uses AC. (Contributed by RP, 24-Nov-2023.) |
⊢ (𝐴 ∈ (ran card ∖ ω) → ∃𝑥 ∈ On 𝑥 = ∩ {𝑦 ∈ On ∣ (∅ ∈ 𝑦 ∧ 𝐴 ≼ (ℵ‘𝑦) ∧ (cf‘(ℵ‘𝑦)) = (ℵ‘𝑦))}) | ||
Theorem | iscard5 43525* | Two ways to express the property of being a cardinal number. (Contributed by RP, 8-Nov-2023.) |
⊢ ((card‘𝐴) = 𝐴 ↔ (𝐴 ∈ On ∧ ∀𝑥 ∈ 𝐴 ¬ 𝑥 ≈ 𝐴)) | ||
Theorem | elrncard 43526* | Let us define a cardinal number to be an element 𝐴 ∈ On such that 𝐴 is not equipotent with any 𝑥 ∈ 𝐴. (Contributed by RP, 1-Oct-2023.) |
⊢ (𝐴 ∈ ran card ↔ (𝐴 ∈ On ∧ ∀𝑥 ∈ 𝐴 ¬ 𝑥 ≈ 𝐴)) | ||
Theorem | harval3 43527* | (har‘𝐴) is the least cardinal that is greater than 𝐴. (Contributed by RP, 4-Nov-2023.) |
⊢ (𝐴 ∈ dom card → (har‘𝐴) = ∩ {𝑥 ∈ ran card ∣ 𝐴 ≺ 𝑥}) | ||
Theorem | harval3on 43528* | For any ordinal number 𝐴 let (har‘𝐴) denote the least cardinal that is greater than 𝐴. (Contributed by RP, 4-Nov-2023.) |
⊢ (𝐴 ∈ On → (har‘𝐴) = ∩ {𝑥 ∈ ran card ∣ 𝐴 ≺ 𝑥}) | ||
Theorem | omssrncard 43529 | All natural numbers are cardinals. (Contributed by RP, 1-Oct-2023.) |
⊢ ω ⊆ ran card | ||
Theorem | 0iscard 43530 | 0 is a cardinal number. (Contributed by RP, 1-Oct-2023.) |
⊢ ∅ ∈ ran card | ||
Theorem | 1iscard 43531 | 1 is a cardinal number. (Contributed by RP, 1-Oct-2023.) |
⊢ 1o ∈ ran card | ||
Theorem | omiscard 43532 | ω is a cardinal number. (Contributed by RP, 1-Oct-2023.) |
⊢ ω ∈ ran card | ||
Theorem | sucomisnotcard 43533 | ω +o 1o is not a cardinal number. (Contributed by RP, 1-Oct-2023.) |
⊢ ¬ (ω +o 1o) ∈ ran card | ||
Theorem | nna1iscard 43534 | For any natural number, the add one operation is results in a cardinal number. (Contributed by RP, 1-Oct-2023.) |
⊢ (𝑁 ∈ ω → (𝑁 +o 1o) ∈ ran card) | ||
Theorem | har2o 43535 | The least cardinal greater than 2 is 3. (Contributed by RP, 5-Nov-2023.) |
⊢ (har‘2o) = 3o | ||
Theorem | en2pr 43536* | A class is equinumerous to ordinal two iff it is a pair of distinct sets. (Contributed by RP, 11-Oct-2023.) |
⊢ (𝐴 ≈ 2o ↔ ∃𝑥∃𝑦(𝐴 = {𝑥, 𝑦} ∧ 𝑥 ≠ 𝑦)) | ||
Theorem | pr2cv 43537 | If an unordered pair is equinumerous to ordinal two, then both parts are sets. (Contributed by RP, 8-Oct-2023.) |
⊢ ({𝐴, 𝐵} ≈ 2o → (𝐴 ∈ V ∧ 𝐵 ∈ V)) | ||
Theorem | pr2el1 43538 | If an unordered pair is equinumerous to ordinal two, then a part is a member. (Contributed by RP, 21-Oct-2023.) |
⊢ ({𝐴, 𝐵} ≈ 2o → 𝐴 ∈ {𝐴, 𝐵}) | ||
Theorem | pr2cv1 43539 | If an unordered pair is equinumerous to ordinal two, then a part is a set. (Contributed by RP, 21-Oct-2023.) |
⊢ ({𝐴, 𝐵} ≈ 2o → 𝐴 ∈ V) | ||
Theorem | pr2el2 43540 | If an unordered pair is equinumerous to ordinal two, then a part is a member. (Contributed by RP, 21-Oct-2023.) |
⊢ ({𝐴, 𝐵} ≈ 2o → 𝐵 ∈ {𝐴, 𝐵}) | ||
Theorem | pr2cv2 43541 | If an unordered pair is equinumerous to ordinal two, then a part is a set. (Contributed by RP, 21-Oct-2023.) |
⊢ ({𝐴, 𝐵} ≈ 2o → 𝐵 ∈ V) | ||
Theorem | pren2 43542 | An unordered pair is equinumerous to ordinal two iff both parts are sets not equal to each other. (Contributed by RP, 8-Oct-2023.) |
⊢ ({𝐴, 𝐵} ≈ 2o ↔ (𝐴 ∈ V ∧ 𝐵 ∈ V ∧ 𝐴 ≠ 𝐵)) | ||
Theorem | pr2eldif1 43543 | If an unordered pair is equinumerous to ordinal two, then a part is an element of the difference of the pair and the singleton of the other part. (Contributed by RP, 21-Oct-2023.) |
⊢ ({𝐴, 𝐵} ≈ 2o → 𝐴 ∈ ({𝐴, 𝐵} ∖ {𝐵})) | ||
Theorem | pr2eldif2 43544 | If an unordered pair is equinumerous to ordinal two, then a part is an element of the difference of the pair and the singleton of the other part. (Contributed by RP, 21-Oct-2023.) |
⊢ ({𝐴, 𝐵} ≈ 2o → 𝐵 ∈ ({𝐴, 𝐵} ∖ {𝐴})) | ||
Theorem | pren2d 43545 | A pair of two distinct sets is equinumerous to ordinal two. (Contributed by RP, 21-Oct-2023.) |
⊢ (𝜑 → 𝐴 ∈ 𝑉) & ⊢ (𝜑 → 𝐵 ∈ 𝑊) & ⊢ (𝜑 → 𝐴 ≠ 𝐵) ⇒ ⊢ (𝜑 → {𝐴, 𝐵} ≈ 2o) | ||
Theorem | aleph1min 43546 | (ℵ‘1o) is the least uncountable ordinal. (Contributed by RP, 18-Nov-2023.) |
⊢ (ℵ‘1o) = ∩ {𝑥 ∈ On ∣ ω ≺ 𝑥} | ||
Theorem | alephiso2 43547 | ℵ is a strictly order-preserving mapping of On onto the class of all infinite cardinal numbers. (Contributed by RP, 18-Nov-2023.) |
⊢ ℵ Isom E , ≺ (On, {𝑥 ∈ ran card ∣ ω ⊆ 𝑥}) | ||
Theorem | alephiso3 43548 | ℵ is a strictly order-preserving mapping of On onto the class of all infinite cardinal numbers. (Contributed by RP, 18-Nov-2023.) |
⊢ ℵ Isom E , ≺ (On, (ran card ∖ ω)) | ||
Theorem | pwelg 43549* | The powerclass is an element of a class closed under union and powerclass operations iff the element is a member of that class. (Contributed by RP, 21-Mar-2020.) |
⊢ (∀𝑥 ∈ 𝐵 (∪ 𝑥 ∈ 𝐵 ∧ 𝒫 𝑥 ∈ 𝐵) → (𝐴 ∈ 𝐵 ↔ 𝒫 𝐴 ∈ 𝐵)) | ||
Theorem | pwinfig 43550* | The powerclass of an infinite set is an infinite set, and vice-versa. Here 𝐵 is a class which is closed under both the union and the powerclass operations and which may have infinite sets as members. (Contributed by RP, 21-Mar-2020.) |
⊢ (∀𝑥 ∈ 𝐵 (∪ 𝑥 ∈ 𝐵 ∧ 𝒫 𝑥 ∈ 𝐵) → (𝐴 ∈ (𝐵 ∖ Fin) ↔ 𝒫 𝐴 ∈ (𝐵 ∖ Fin))) | ||
Theorem | pwinfi2 43551 | The powerclass of an infinite set is an infinite set, and vice-versa. Here 𝑈 is a weak universe. (Contributed by RP, 21-Mar-2020.) |
⊢ (𝑈 ∈ WUni → (𝐴 ∈ (𝑈 ∖ Fin) ↔ 𝒫 𝐴 ∈ (𝑈 ∖ Fin))) | ||
Theorem | pwinfi3 43552 | The powerclass of an infinite set is an infinite set, and vice-versa. Here 𝑇 is a transitive Tarski universe. (Contributed by RP, 21-Mar-2020.) |
⊢ ((𝑇 ∈ Tarski ∧ Tr 𝑇) → (𝐴 ∈ (𝑇 ∖ Fin) ↔ 𝒫 𝐴 ∈ (𝑇 ∖ Fin))) | ||
Theorem | pwinfi 43553 | The powerclass of an infinite set is an infinite set, and vice-versa. (Contributed by RP, 21-Mar-2020.) |
⊢ (𝐴 ∈ (V ∖ Fin) ↔ 𝒫 𝐴 ∈ (V ∖ Fin)) | ||
While there is not yet a definition, the finite intersection property of a class is introduced by fiint 9363 where two textbook definitions are shown to be equivalent. This property is seen often with ordinal numbers (onin 6416, ordelinel 6486), chains of sets ordered by the proper subset relation (sorpssin 7749), various sets in the field of topology (inopn 22920, incld 23066, innei 23148, ... ) and "universal" classes like weak universes (wunin 10750, tskin 10796) and the class of all sets (inex1g 5324). | ||
Theorem | fipjust 43554* | A definition of the finite intersection property of a class based on closure under pairwise intersection of its elements is independent of the dummy variables. (Contributed by RP, 1-Jan-2020.) |
⊢ (∀𝑢 ∈ 𝐴 ∀𝑣 ∈ 𝐴 (𝑢 ∩ 𝑣) ∈ 𝐴 ↔ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝑥 ∩ 𝑦) ∈ 𝐴) | ||
Theorem | cllem0 43555* | The class of all sets with property 𝜑(𝑧) is closed under the binary operation on sets defined in 𝑅(𝑥, 𝑦). (Contributed by RP, 3-Jan-2020.) |
⊢ 𝑉 = {𝑧 ∣ 𝜑} & ⊢ 𝑅 ∈ 𝑈 & ⊢ (𝑧 = 𝑅 → (𝜑 ↔ 𝜓)) & ⊢ (𝑧 = 𝑥 → (𝜑 ↔ 𝜒)) & ⊢ (𝑧 = 𝑦 → (𝜑 ↔ 𝜃)) & ⊢ ((𝜒 ∧ 𝜃) → 𝜓) ⇒ ⊢ ∀𝑥 ∈ 𝑉 ∀𝑦 ∈ 𝑉 𝑅 ∈ 𝑉 | ||
Theorem | superficl 43556* | The class of all supersets of a class has the finite intersection property. (Contributed by RP, 1-Jan-2020.) (Proof shortened by RP, 3-Jan-2020.) |
⊢ 𝐴 = {𝑧 ∣ 𝐵 ⊆ 𝑧} ⇒ ⊢ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝑥 ∩ 𝑦) ∈ 𝐴 | ||
Theorem | superuncl 43557* | The class of all supersets of a class is closed under binary union. (Contributed by RP, 3-Jan-2020.) |
⊢ 𝐴 = {𝑧 ∣ 𝐵 ⊆ 𝑧} ⇒ ⊢ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝑥 ∪ 𝑦) ∈ 𝐴 | ||
Theorem | ssficl 43558* | The class of all subsets of a class has the finite intersection property. (Contributed by RP, 1-Jan-2020.) (Proof shortened by RP, 3-Jan-2020.) |
⊢ 𝐴 = {𝑧 ∣ 𝑧 ⊆ 𝐵} ⇒ ⊢ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝑥 ∩ 𝑦) ∈ 𝐴 | ||
Theorem | ssuncl 43559* | The class of all subsets of a class is closed under binary union. (Contributed by RP, 3-Jan-2020.) |
⊢ 𝐴 = {𝑧 ∣ 𝑧 ⊆ 𝐵} ⇒ ⊢ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝑥 ∪ 𝑦) ∈ 𝐴 | ||
Theorem | ssdifcl 43560* | The class of all subsets of a class is closed under class difference. (Contributed by RP, 3-Jan-2020.) |
⊢ 𝐴 = {𝑧 ∣ 𝑧 ⊆ 𝐵} ⇒ ⊢ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝑥 ∖ 𝑦) ∈ 𝐴 | ||
Theorem | sssymdifcl 43561* | The class of all subsets of a class is closed under symmetric difference. (Contributed by RP, 3-Jan-2020.) |
⊢ 𝐴 = {𝑧 ∣ 𝑧 ⊆ 𝐵} ⇒ ⊢ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 ((𝑥 ∖ 𝑦) ∪ (𝑦 ∖ 𝑥)) ∈ 𝐴 | ||
Theorem | fiinfi 43562* | If two classes have the finite intersection property, then so does their intersection. (Contributed by RP, 1-Jan-2020.) |
⊢ (𝜑 → ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝑥 ∩ 𝑦) ∈ 𝐴) & ⊢ (𝜑 → ∀𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 (𝑥 ∩ 𝑦) ∈ 𝐵) & ⊢ (𝜑 → 𝐶 = (𝐴 ∩ 𝐵)) ⇒ ⊢ (𝜑 → ∀𝑥 ∈ 𝐶 ∀𝑦 ∈ 𝐶 (𝑥 ∩ 𝑦) ∈ 𝐶) | ||
Theorem | rababg 43563 | Condition when restricted class is equal to unrestricted class. (Contributed by RP, 13-Aug-2020.) |
⊢ (∀𝑥(𝜑 → 𝑥 ∈ 𝐴) ↔ {𝑥 ∈ 𝐴 ∣ 𝜑} = {𝑥 ∣ 𝜑}) | ||
Theorem | elinintab 43564* | Two ways of saying a set is an element of the intersection of a class with the intersection of a class. (Contributed by RP, 13-Aug-2020.) |
⊢ (𝐴 ∈ (𝐵 ∩ ∩ {𝑥 ∣ 𝜑}) ↔ (𝐴 ∈ 𝐵 ∧ ∀𝑥(𝜑 → 𝐴 ∈ 𝑥))) | ||
Theorem | elmapintrab 43565* | Two ways to say a set is an element of the intersection of a class of images. (Contributed by RP, 16-Aug-2020.) |
⊢ 𝐶 ∈ V & ⊢ 𝐶 ⊆ 𝐵 ⇒ ⊢ (𝐴 ∈ 𝑉 → (𝐴 ∈ ∩ {𝑤 ∈ 𝒫 𝐵 ∣ ∃𝑥(𝑤 = 𝐶 ∧ 𝜑)} ↔ ((∃𝑥𝜑 → 𝐴 ∈ 𝐵) ∧ ∀𝑥(𝜑 → 𝐴 ∈ 𝐶)))) | ||
Theorem | elinintrab 43566* | Two ways of saying a set is an element of the intersection of a class with the intersection of a class. (Contributed by RP, 14-Aug-2020.) |
⊢ (𝐴 ∈ 𝑉 → (𝐴 ∈ ∩ {𝑤 ∈ 𝒫 𝐵 ∣ ∃𝑥(𝑤 = (𝐵 ∩ 𝑥) ∧ 𝜑)} ↔ ((∃𝑥𝜑 → 𝐴 ∈ 𝐵) ∧ ∀𝑥(𝜑 → 𝐴 ∈ 𝑥)))) | ||
Theorem | inintabss 43567* | Upper bound on intersection of class and the intersection of a class. (Contributed by RP, 13-Aug-2020.) |
⊢ (𝐴 ∩ ∩ {𝑥 ∣ 𝜑}) ⊆ ∩ {𝑤 ∈ 𝒫 𝐴 ∣ ∃𝑥(𝑤 = (𝐴 ∩ 𝑥) ∧ 𝜑)} | ||
Theorem | inintabd 43568* | Value of the intersection of class with the intersection of a nonempty class. (Contributed by RP, 13-Aug-2020.) |
⊢ (𝜑 → ∃𝑥𝜓) ⇒ ⊢ (𝜑 → (𝐴 ∩ ∩ {𝑥 ∣ 𝜓}) = ∩ {𝑤 ∈ 𝒫 𝐴 ∣ ∃𝑥(𝑤 = (𝐴 ∩ 𝑥) ∧ 𝜓)}) | ||
Theorem | xpinintabd 43569* | Value of the intersection of Cartesian product with the intersection of a nonempty class. (Contributed by RP, 12-Aug-2020.) |
⊢ (𝜑 → ∃𝑥𝜓) ⇒ ⊢ (𝜑 → ((𝐴 × 𝐵) ∩ ∩ {𝑥 ∣ 𝜓}) = ∩ {𝑤 ∈ 𝒫 (𝐴 × 𝐵) ∣ ∃𝑥(𝑤 = ((𝐴 × 𝐵) ∩ 𝑥) ∧ 𝜓)}) | ||
Theorem | relintabex 43570 | If the intersection of a class is a relation, then the class is nonempty. (Contributed by RP, 12-Aug-2020.) |
⊢ (Rel ∩ {𝑥 ∣ 𝜑} → ∃𝑥𝜑) | ||
Theorem | elcnvcnvintab 43571* | Two ways of saying a set is an element of the converse of the converse of the intersection of a class. (Contributed by RP, 20-Aug-2020.) |
⊢ (𝐴 ∈ ◡◡∩ {𝑥 ∣ 𝜑} ↔ (𝐴 ∈ (V × V) ∧ ∀𝑥(𝜑 → 𝐴 ∈ 𝑥))) | ||
Theorem | relintab 43572* | Value of the intersection of a class when it is a relation. (Contributed by RP, 12-Aug-2020.) |
⊢ (Rel ∩ {𝑥 ∣ 𝜑} → ∩ {𝑥 ∣ 𝜑} = ∩ {𝑤 ∈ 𝒫 (V × V) ∣ ∃𝑥(𝑤 = ◡◡𝑥 ∧ 𝜑)}) | ||
Theorem | nonrel 43573 | A non-relation is equal to the base class with all ordered pairs removed. (Contributed by RP, 25-Oct-2020.) |
⊢ (𝐴 ∖ ◡◡𝐴) = (𝐴 ∖ (V × V)) | ||
Theorem | elnonrel 43574 | Only an ordered pair where not both entries are sets could be an element of the non-relation part of class. (Contributed by RP, 25-Oct-2020.) |
⊢ (〈𝑋, 𝑌〉 ∈ (𝐴 ∖ ◡◡𝐴) ↔ (∅ ∈ 𝐴 ∧ ¬ (𝑋 ∈ V ∧ 𝑌 ∈ V))) | ||
Theorem | cnvssb 43575 | Subclass theorem for converse. (Contributed by RP, 22-Oct-2020.) |
⊢ (Rel 𝐴 → (𝐴 ⊆ 𝐵 ↔ ◡𝐴 ⊆ ◡𝐵)) | ||
Theorem | relnonrel 43576 | The non-relation part of a relation is empty. (Contributed by RP, 22-Oct-2020.) |
⊢ (Rel 𝐴 ↔ (𝐴 ∖ ◡◡𝐴) = ∅) | ||
Theorem | cnvnonrel 43577 | The converse of the non-relation part of a class is empty. (Contributed by RP, 18-Oct-2020.) |
⊢ ◡(𝐴 ∖ ◡◡𝐴) = ∅ | ||
Theorem | brnonrel 43578 | A non-relation cannot relate any two classes. (Contributed by RP, 23-Oct-2020.) |
⊢ ((𝑋 ∈ 𝑈 ∧ 𝑌 ∈ 𝑉) → ¬ 𝑋(𝐴 ∖ ◡◡𝐴)𝑌) | ||
Theorem | dmnonrel 43579 | The domain of the non-relation part of a class is empty. (Contributed by RP, 22-Oct-2020.) |
⊢ dom (𝐴 ∖ ◡◡𝐴) = ∅ | ||
Theorem | rnnonrel 43580 | The range of the non-relation part of a class is empty. (Contributed by RP, 22-Oct-2020.) |
⊢ ran (𝐴 ∖ ◡◡𝐴) = ∅ | ||
Theorem | resnonrel 43581 | A restriction of the non-relation part of a class is empty. (Contributed by RP, 22-Oct-2020.) |
⊢ ((𝐴 ∖ ◡◡𝐴) ↾ 𝐵) = ∅ | ||
Theorem | imanonrel 43582 | An image under the non-relation part of a class is empty. (Contributed by RP, 22-Oct-2020.) |
⊢ ((𝐴 ∖ ◡◡𝐴) “ 𝐵) = ∅ | ||
Theorem | cononrel1 43583 | Composition with the non-relation part of a class is empty. (Contributed by RP, 22-Oct-2020.) |
⊢ ((𝐴 ∖ ◡◡𝐴) ∘ 𝐵) = ∅ | ||
Theorem | cononrel2 43584 | Composition with the non-relation part of a class is empty. (Contributed by RP, 22-Oct-2020.) |
⊢ (𝐴 ∘ (𝐵 ∖ ◡◡𝐵)) = ∅ | ||
See also idssxp 6068 by Thierry Arnoux. | ||
Theorem | elmapintab 43585* | Two ways to say a set is an element of mapped intersection of a class. Here 𝐹 maps elements of 𝐶 to elements of ∩ {𝑥 ∣ 𝜑} or 𝑥. (Contributed by RP, 19-Aug-2020.) |
⊢ (𝐴 ∈ 𝐵 ↔ (𝐴 ∈ 𝐶 ∧ (𝐹‘𝐴) ∈ ∩ {𝑥 ∣ 𝜑})) & ⊢ (𝐴 ∈ 𝐸 ↔ (𝐴 ∈ 𝐶 ∧ (𝐹‘𝐴) ∈ 𝑥)) ⇒ ⊢ (𝐴 ∈ 𝐵 ↔ (𝐴 ∈ 𝐶 ∧ ∀𝑥(𝜑 → 𝐴 ∈ 𝐸))) | ||
Theorem | fvnonrel 43586 | The function value of any class under a non-relation is empty. (Contributed by RP, 23-Oct-2020.) |
⊢ ((𝐴 ∖ ◡◡𝐴)‘𝑋) = ∅ | ||
Theorem | elinlem 43587 | Two ways to say a set is a member of an intersection. (Contributed by RP, 19-Aug-2020.) |
⊢ (𝐴 ∈ (𝐵 ∩ 𝐶) ↔ (𝐴 ∈ 𝐵 ∧ ( I ‘𝐴) ∈ 𝐶)) | ||
Theorem | elcnvcnvlem 43588 | Two ways to say a set is a member of the converse of the converse of a class. (Contributed by RP, 20-Aug-2020.) |
⊢ (𝐴 ∈ ◡◡𝐵 ↔ (𝐴 ∈ (V × V) ∧ ( I ‘𝐴) ∈ 𝐵)) | ||
Original probably needs new subsection for Relation-related existence theorems. | ||
Theorem | cnvcnvintabd 43589* | Value of the relationship content of the intersection of a class. (Contributed by RP, 20-Aug-2020.) |
⊢ (𝜑 → ∃𝑥𝜓) ⇒ ⊢ (𝜑 → ◡◡∩ {𝑥 ∣ 𝜓} = ∩ {𝑤 ∈ 𝒫 (V × V) ∣ ∃𝑥(𝑤 = ◡◡𝑥 ∧ 𝜓)}) | ||
Theorem | elcnvlem 43590 | Two ways to say a set is a member of the converse of a class. (Contributed by RP, 19-Aug-2020.) |
⊢ 𝐹 = (𝑥 ∈ (V × V) ↦ 〈(2nd ‘𝑥), (1st ‘𝑥)〉) ⇒ ⊢ (𝐴 ∈ ◡𝐵 ↔ (𝐴 ∈ (V × V) ∧ (𝐹‘𝐴) ∈ 𝐵)) | ||
Theorem | elcnvintab 43591* | Two ways of saying a set is an element of the converse of the intersection of a class. (Contributed by RP, 19-Aug-2020.) |
⊢ (𝐴 ∈ ◡∩ {𝑥 ∣ 𝜑} ↔ (𝐴 ∈ (V × V) ∧ ∀𝑥(𝜑 → 𝐴 ∈ ◡𝑥))) | ||
Theorem | cnvintabd 43592* | Value of the converse of the intersection of a nonempty class. (Contributed by RP, 20-Aug-2020.) |
⊢ (𝜑 → ∃𝑥𝜓) ⇒ ⊢ (𝜑 → ◡∩ {𝑥 ∣ 𝜓} = ∩ {𝑤 ∈ 𝒫 (V × V) ∣ ∃𝑥(𝑤 = ◡𝑥 ∧ 𝜓)}) | ||
Theorem | undmrnresiss 43593* | Two ways of saying the identity relation restricted to the union of the domain and range of a relation is a subset of a relation. Generalization of reflexg 43594. (Contributed by RP, 26-Sep-2020.) |
⊢ (( I ↾ (dom 𝐴 ∪ ran 𝐴)) ⊆ 𝐵 ↔ ∀𝑥∀𝑦(𝑥𝐴𝑦 → (𝑥𝐵𝑥 ∧ 𝑦𝐵𝑦))) | ||
Theorem | reflexg 43594* | Two ways of saying a relation is reflexive over its domain and range. (Contributed by RP, 4-Aug-2020.) |
⊢ (( I ↾ (dom 𝐴 ∪ ran 𝐴)) ⊆ 𝐴 ↔ ∀𝑥∀𝑦(𝑥𝐴𝑦 → (𝑥𝐴𝑥 ∧ 𝑦𝐴𝑦))) | ||
Theorem | cnvssco 43595* | A condition weaker than reflexivity. (Contributed by RP, 3-Aug-2020.) |
⊢ (◡𝐴 ⊆ ◡(𝐵 ∘ 𝐶) ↔ ∀𝑥∀𝑦∃𝑧(𝑥𝐴𝑦 → (𝑥𝐶𝑧 ∧ 𝑧𝐵𝑦))) | ||
Theorem | refimssco 43596 | Reflexive relations are subsets of their self-composition. (Contributed by RP, 4-Aug-2020.) |
⊢ (( I ↾ (dom 𝐴 ∪ ran 𝐴)) ⊆ 𝐴 → ◡𝐴 ⊆ ◡(𝐴 ∘ 𝐴)) | ||
Theorem | cleq2lem 43597 | Equality implies bijection. (Contributed by RP, 24-Jul-2020.) |
⊢ (𝐴 = 𝐵 → (𝜑 ↔ 𝜓)) ⇒ ⊢ (𝐴 = 𝐵 → ((𝑅 ⊆ 𝐴 ∧ 𝜑) ↔ (𝑅 ⊆ 𝐵 ∧ 𝜓))) | ||
Theorem | cbvcllem 43598* | Change of bound variable in class of supersets of a with a property. (Contributed by RP, 24-Jul-2020.) |
⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜓)) ⇒ ⊢ {𝑥 ∣ (𝑋 ⊆ 𝑥 ∧ 𝜑)} = {𝑦 ∣ (𝑋 ⊆ 𝑦 ∧ 𝜓)} | ||
Theorem | clublem 43599* | If a superset 𝑌 of 𝑋 possesses the property parameterized in 𝑥 in 𝜓, then 𝑌 is a superset of the closure of that property for the set 𝑋. (Contributed by RP, 23-Jul-2020.) |
⊢ (𝜑 → 𝑌 ∈ V) & ⊢ (𝑥 = 𝑌 → (𝜓 ↔ 𝜒)) & ⊢ (𝜑 → 𝑋 ⊆ 𝑌) & ⊢ (𝜑 → 𝜒) ⇒ ⊢ (𝜑 → ∩ {𝑥 ∣ (𝑋 ⊆ 𝑥 ∧ 𝜓)} ⊆ 𝑌) | ||
Theorem | clss2lem 43600* | The closure of a property is a superset of the closure of a less restrictive property. (Contributed by RP, 24-Jul-2020.) |
⊢ (𝜑 → (𝜒 → 𝜓)) ⇒ ⊢ (𝜑 → ∩ {𝑥 ∣ (𝑋 ⊆ 𝑥 ∧ 𝜓)} ⊆ ∩ {𝑥 ∣ (𝑋 ⊆ 𝑥 ∧ 𝜒)}) |
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