![]() |
Metamath
Proof Explorer Theorem List (p. 99 of 437) | < Previous Next > |
Bad symbols? Try the
GIF version. |
||
Mirrors > Metamath Home Page > MPE Home Page > Theorem List Contents > Recent Proofs This page: Page List |
Color key: | ![]() (1-28347) |
![]() (28348-29872) |
![]() (29873-43657) |
Type | Label | Description |
---|---|---|
Statement | ||
Theorem | fpwwecbv 9801* | Lemma for fpwwe 9803. (Contributed by Mario Carneiro, 15-May-2015.) |
⊢ 𝑊 = {〈𝑥, 𝑟〉 ∣ ((𝑥 ⊆ 𝐴 ∧ 𝑟 ⊆ (𝑥 × 𝑥)) ∧ (𝑟 We 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝐹‘(◡𝑟 “ {𝑦})) = 𝑦))} ⇒ ⊢ 𝑊 = {〈𝑎, 𝑠〉 ∣ ((𝑎 ⊆ 𝐴 ∧ 𝑠 ⊆ (𝑎 × 𝑎)) ∧ (𝑠 We 𝑎 ∧ ∀𝑧 ∈ 𝑎 (𝐹‘(◡𝑠 “ {𝑧})) = 𝑧))} | ||
Theorem | fpwwelem 9802* | Lemma for fpwwe 9803. (Contributed by Mario Carneiro, 15-May-2015.) |
⊢ 𝑊 = {〈𝑥, 𝑟〉 ∣ ((𝑥 ⊆ 𝐴 ∧ 𝑟 ⊆ (𝑥 × 𝑥)) ∧ (𝑟 We 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝐹‘(◡𝑟 “ {𝑦})) = 𝑦))} & ⊢ (𝜑 → 𝐴 ∈ V) ⇒ ⊢ (𝜑 → (𝑋𝑊𝑅 ↔ ((𝑋 ⊆ 𝐴 ∧ 𝑅 ⊆ (𝑋 × 𝑋)) ∧ (𝑅 We 𝑋 ∧ ∀𝑦 ∈ 𝑋 (𝐹‘(◡𝑅 “ {𝑦})) = 𝑦)))) | ||
Theorem | fpwwe 9803* | Given any function 𝐹 from the powerset of 𝐴 to 𝐴, canth2 8401 gives that the function is not injective, but we can say rather more than that. There is a unique well-ordered subset 〈𝑋, (𝑊‘𝑋)〉 which "agrees" with 𝐹 in the sense that each initial segment maps to its upper bound, and such that the entire set maps to an element of the set (so that it cannot be extended without losing the well-ordering). This theorem can be used to prove dfac8a 9186. Theorem 1.1 of [KanamoriPincus] p. 415. (Contributed by Mario Carneiro, 18-May-2015.) |
⊢ 𝑊 = {〈𝑥, 𝑟〉 ∣ ((𝑥 ⊆ 𝐴 ∧ 𝑟 ⊆ (𝑥 × 𝑥)) ∧ (𝑟 We 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝐹‘(◡𝑟 “ {𝑦})) = 𝑦))} & ⊢ (𝜑 → 𝐴 ∈ V) & ⊢ ((𝜑 ∧ 𝑥 ∈ (𝒫 𝐴 ∩ dom card)) → (𝐹‘𝑥) ∈ 𝐴) & ⊢ 𝑋 = ∪ dom 𝑊 ⇒ ⊢ (𝜑 → ((𝑌𝑊𝑅 ∧ (𝐹‘𝑌) ∈ 𝑌) ↔ (𝑌 = 𝑋 ∧ 𝑅 = (𝑊‘𝑋)))) | ||
Theorem | canth4 9804* | An "effective" form of Cantor's theorem canth 6880. For any function 𝐹 from the powerset of 𝐴 to 𝐴, there are two definable sets 𝐵 and 𝐶 which witness non-injectivity of 𝐹. Corollary 1.3 of [KanamoriPincus] p. 416. (Contributed by Mario Carneiro, 18-May-2015.) |
⊢ 𝑊 = {〈𝑥, 𝑟〉 ∣ ((𝑥 ⊆ 𝐴 ∧ 𝑟 ⊆ (𝑥 × 𝑥)) ∧ (𝑟 We 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝐹‘(◡𝑟 “ {𝑦})) = 𝑦))} & ⊢ 𝐵 = ∪ dom 𝑊 & ⊢ 𝐶 = (◡(𝑊‘𝐵) “ {(𝐹‘𝐵)}) ⇒ ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐹:𝐷⟶𝐴 ∧ (𝒫 𝐴 ∩ dom card) ⊆ 𝐷) → (𝐵 ⊆ 𝐴 ∧ 𝐶 ⊊ 𝐵 ∧ (𝐹‘𝐵) = (𝐹‘𝐶))) | ||
Theorem | canthnumlem 9805* | Lemma for canthnum 9806. (Contributed by Mario Carneiro, 19-May-2015.) |
⊢ 𝑊 = {〈𝑥, 𝑟〉 ∣ ((𝑥 ⊆ 𝐴 ∧ 𝑟 ⊆ (𝑥 × 𝑥)) ∧ (𝑟 We 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝐹‘(◡𝑟 “ {𝑦})) = 𝑦))} & ⊢ 𝐵 = ∪ dom 𝑊 & ⊢ 𝐶 = (◡(𝑊‘𝐵) “ {(𝐹‘𝐵)}) ⇒ ⊢ (𝐴 ∈ 𝑉 → ¬ 𝐹:(𝒫 𝐴 ∩ dom card)–1-1→𝐴) | ||
Theorem | canthnum 9806 | The set of well-orderable subsets of a set 𝐴 strictly dominates 𝐴. A stronger form of canth2 8401. Corollary 1.4(a) of [KanamoriPincus] p. 417. (Contributed by Mario Carneiro, 19-May-2015.) |
⊢ (𝐴 ∈ 𝑉 → 𝐴 ≺ (𝒫 𝐴 ∩ dom card)) | ||
Theorem | canthwelem 9807* | Lemma for canthwe 9808. (Contributed by Mario Carneiro, 31-May-2015.) |
⊢ 𝑂 = {〈𝑥, 𝑟〉 ∣ (𝑥 ⊆ 𝐴 ∧ 𝑟 ⊆ (𝑥 × 𝑥) ∧ 𝑟 We 𝑥)} & ⊢ 𝑊 = {〈𝑥, 𝑟〉 ∣ ((𝑥 ⊆ 𝐴 ∧ 𝑟 ⊆ (𝑥 × 𝑥)) ∧ (𝑟 We 𝑥 ∧ ∀𝑦 ∈ 𝑥 [(◡𝑟 “ {𝑦}) / 𝑢](𝑢𝐹(𝑟 ∩ (𝑢 × 𝑢))) = 𝑦))} & ⊢ 𝐵 = ∪ dom 𝑊 & ⊢ 𝐶 = (◡(𝑊‘𝐵) “ {(𝐵𝐹(𝑊‘𝐵))}) ⇒ ⊢ (𝐴 ∈ 𝑉 → ¬ 𝐹:𝑂–1-1→𝐴) | ||
Theorem | canthwe 9808* | The set of well-orders of a set 𝐴 strictly dominates 𝐴. A stronger form of canth2 8401. Corollary 1.4(b) of [KanamoriPincus] p. 417. (Contributed by Mario Carneiro, 31-May-2015.) |
⊢ 𝑂 = {〈𝑥, 𝑟〉 ∣ (𝑥 ⊆ 𝐴 ∧ 𝑟 ⊆ (𝑥 × 𝑥) ∧ 𝑟 We 𝑥)} ⇒ ⊢ (𝐴 ∈ 𝑉 → 𝐴 ≺ 𝑂) | ||
Theorem | canthp1lem1 9809 | Lemma for canthp1 9811. (Contributed by Mario Carneiro, 18-May-2015.) |
⊢ (1o ≺ 𝐴 → (𝐴 +𝑐 2o) ≼ 𝒫 𝐴) | ||
Theorem | canthp1lem2 9810* | Lemma for canthp1 9811. (Contributed by Mario Carneiro, 18-May-2015.) |
⊢ (𝜑 → 1o ≺ 𝐴) & ⊢ (𝜑 → 𝐹:𝒫 𝐴–1-1-onto→(𝐴 +𝑐 1o)) & ⊢ (𝜑 → 𝐺:((𝐴 +𝑐 1o) ∖ {(𝐹‘𝐴)})–1-1-onto→𝐴) & ⊢ 𝐻 = ((𝐺 ∘ 𝐹) ∘ (𝑥 ∈ 𝒫 𝐴 ↦ if(𝑥 = 𝐴, ∅, 𝑥))) & ⊢ 𝑊 = {〈𝑥, 𝑟〉 ∣ ((𝑥 ⊆ 𝐴 ∧ 𝑟 ⊆ (𝑥 × 𝑥)) ∧ (𝑟 We 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝐻‘(◡𝑟 “ {𝑦})) = 𝑦))} & ⊢ 𝐵 = ∪ dom 𝑊 ⇒ ⊢ ¬ 𝜑 | ||
Theorem | canthp1 9811 | A slightly stronger form of Cantor's theorem: For 1 < 𝑛, 𝑛 + 1 < 2↑𝑛. Corollary 1.6 of [KanamoriPincus] p. 417. (Contributed by Mario Carneiro, 18-May-2015.) |
⊢ (1o ≺ 𝐴 → (𝐴 +𝑐 1o) ≺ 𝒫 𝐴) | ||
Theorem | finngch 9812 | The exclusion of finite sets from consideration in df-gch 9778 is necessary, because otherwise finite sets larger than a singleton would violate the GCH property. (Contributed by Mario Carneiro, 10-Jun-2015.) |
⊢ ((𝐴 ∈ Fin ∧ 1o ≺ 𝐴) → (𝐴 ≺ (𝐴 +𝑐 1o) ∧ (𝐴 +𝑐 1o) ≺ 𝒫 𝐴)) | ||
Theorem | gchcda1 9813 | An infinite GCH-set is idempotent under cardinal successor. (Contributed by Mario Carneiro, 18-May-2015.) |
⊢ ((𝐴 ∈ GCH ∧ ¬ 𝐴 ∈ Fin) → (𝐴 +𝑐 1o) ≈ 𝐴) | ||
Theorem | gchinf 9814 | An infinite GCH-set is Dedekind-infinite. (Contributed by Mario Carneiro, 31-May-2015.) |
⊢ ((𝐴 ∈ GCH ∧ ¬ 𝐴 ∈ Fin) → ω ≼ 𝐴) | ||
Theorem | pwfseqlem1 9815* | Lemma for pwfseq 9821. Derive a contradiction by diagonalization. (Contributed by Mario Carneiro, 31-May-2015.) |
⊢ (𝜑 → 𝐺:𝒫 𝐴–1-1→∪ 𝑛 ∈ ω (𝐴 ↑𝑚 𝑛)) & ⊢ (𝜑 → 𝑋 ⊆ 𝐴) & ⊢ (𝜑 → 𝐻:ω–1-1-onto→𝑋) & ⊢ (𝜓 ↔ ((𝑥 ⊆ 𝐴 ∧ 𝑟 ⊆ (𝑥 × 𝑥) ∧ 𝑟 We 𝑥) ∧ ω ≼ 𝑥)) & ⊢ ((𝜑 ∧ 𝜓) → 𝐾:∪ 𝑛 ∈ ω (𝑥 ↑𝑚 𝑛)–1-1→𝑥) & ⊢ 𝐷 = (𝐺‘{𝑤 ∈ 𝑥 ∣ ((◡𝐾‘𝑤) ∈ ran 𝐺 ∧ ¬ 𝑤 ∈ (◡𝐺‘(◡𝐾‘𝑤)))}) ⇒ ⊢ ((𝜑 ∧ 𝜓) → 𝐷 ∈ (∪ 𝑛 ∈ ω (𝐴 ↑𝑚 𝑛) ∖ ∪ 𝑛 ∈ ω (𝑥 ↑𝑚 𝑛))) | ||
Theorem | pwfseqlem2 9816* | Lemma for pwfseq 9821. (Contributed by Mario Carneiro, 18-Nov-2014.) (Revised by AV, 18-Sep-2021.) |
⊢ (𝜑 → 𝐺:𝒫 𝐴–1-1→∪ 𝑛 ∈ ω (𝐴 ↑𝑚 𝑛)) & ⊢ (𝜑 → 𝑋 ⊆ 𝐴) & ⊢ (𝜑 → 𝐻:ω–1-1-onto→𝑋) & ⊢ (𝜓 ↔ ((𝑥 ⊆ 𝐴 ∧ 𝑟 ⊆ (𝑥 × 𝑥) ∧ 𝑟 We 𝑥) ∧ ω ≼ 𝑥)) & ⊢ ((𝜑 ∧ 𝜓) → 𝐾:∪ 𝑛 ∈ ω (𝑥 ↑𝑚 𝑛)–1-1→𝑥) & ⊢ 𝐷 = (𝐺‘{𝑤 ∈ 𝑥 ∣ ((◡𝐾‘𝑤) ∈ ran 𝐺 ∧ ¬ 𝑤 ∈ (◡𝐺‘(◡𝐾‘𝑤)))}) & ⊢ 𝐹 = (𝑥 ∈ V, 𝑟 ∈ V ↦ if(𝑥 ∈ Fin, (𝐻‘(card‘𝑥)), (𝐷‘∩ {𝑧 ∈ ω ∣ ¬ (𝐷‘𝑧) ∈ 𝑥}))) ⇒ ⊢ ((𝑌 ∈ Fin ∧ 𝑅 ∈ 𝑉) → (𝑌𝐹𝑅) = (𝐻‘(card‘𝑌))) | ||
Theorem | pwfseqlem3 9817* | Lemma for pwfseq 9821. Using the construction 𝐷 from pwfseqlem1 9815, produce a function 𝐹 that maps any well-ordered infinite set to an element outside the set. (Contributed by Mario Carneiro, 31-May-2015.) |
⊢ (𝜑 → 𝐺:𝒫 𝐴–1-1→∪ 𝑛 ∈ ω (𝐴 ↑𝑚 𝑛)) & ⊢ (𝜑 → 𝑋 ⊆ 𝐴) & ⊢ (𝜑 → 𝐻:ω–1-1-onto→𝑋) & ⊢ (𝜓 ↔ ((𝑥 ⊆ 𝐴 ∧ 𝑟 ⊆ (𝑥 × 𝑥) ∧ 𝑟 We 𝑥) ∧ ω ≼ 𝑥)) & ⊢ ((𝜑 ∧ 𝜓) → 𝐾:∪ 𝑛 ∈ ω (𝑥 ↑𝑚 𝑛)–1-1→𝑥) & ⊢ 𝐷 = (𝐺‘{𝑤 ∈ 𝑥 ∣ ((◡𝐾‘𝑤) ∈ ran 𝐺 ∧ ¬ 𝑤 ∈ (◡𝐺‘(◡𝐾‘𝑤)))}) & ⊢ 𝐹 = (𝑥 ∈ V, 𝑟 ∈ V ↦ if(𝑥 ∈ Fin, (𝐻‘(card‘𝑥)), (𝐷‘∩ {𝑧 ∈ ω ∣ ¬ (𝐷‘𝑧) ∈ 𝑥}))) ⇒ ⊢ ((𝜑 ∧ 𝜓) → (𝑥𝐹𝑟) ∈ (𝐴 ∖ 𝑥)) | ||
Theorem | pwfseqlem4a 9818* | Lemma for pwfseqlem4 9819. (Contributed by Mario Carneiro, 7-Jun-2016.) |
⊢ (𝜑 → 𝐺:𝒫 𝐴–1-1→∪ 𝑛 ∈ ω (𝐴 ↑𝑚 𝑛)) & ⊢ (𝜑 → 𝑋 ⊆ 𝐴) & ⊢ (𝜑 → 𝐻:ω–1-1-onto→𝑋) & ⊢ (𝜓 ↔ ((𝑥 ⊆ 𝐴 ∧ 𝑟 ⊆ (𝑥 × 𝑥) ∧ 𝑟 We 𝑥) ∧ ω ≼ 𝑥)) & ⊢ ((𝜑 ∧ 𝜓) → 𝐾:∪ 𝑛 ∈ ω (𝑥 ↑𝑚 𝑛)–1-1→𝑥) & ⊢ 𝐷 = (𝐺‘{𝑤 ∈ 𝑥 ∣ ((◡𝐾‘𝑤) ∈ ran 𝐺 ∧ ¬ 𝑤 ∈ (◡𝐺‘(◡𝐾‘𝑤)))}) & ⊢ 𝐹 = (𝑥 ∈ V, 𝑟 ∈ V ↦ if(𝑥 ∈ Fin, (𝐻‘(card‘𝑥)), (𝐷‘∩ {𝑧 ∈ ω ∣ ¬ (𝐷‘𝑧) ∈ 𝑥}))) ⇒ ⊢ ((𝜑 ∧ (𝑎 ⊆ 𝐴 ∧ 𝑠 ⊆ (𝑎 × 𝑎) ∧ 𝑠 We 𝑎)) → (𝑎𝐹𝑠) ∈ 𝐴) | ||
Theorem | pwfseqlem4 9819* | Lemma for pwfseq 9821. Derive a final contradiction from the function 𝐹 in pwfseqlem3 9817. Applying fpwwe2 9800 to it, we get a certain maximal well-ordered subset 𝑍, but the defining property (𝑍𝐹(𝑊‘𝑍)) ∈ 𝑍 contradicts our assumption on 𝐹, so we are reduced to the case of 𝑍 finite. This too is a contradiction, though, because 𝑍 and its preimage under (𝑊‘𝑍) are distinct sets of the same cardinality and in a subset relation, which is impossible for finite sets. (Contributed by Mario Carneiro, 31-May-2015.) |
⊢ (𝜑 → 𝐺:𝒫 𝐴–1-1→∪ 𝑛 ∈ ω (𝐴 ↑𝑚 𝑛)) & ⊢ (𝜑 → 𝑋 ⊆ 𝐴) & ⊢ (𝜑 → 𝐻:ω–1-1-onto→𝑋) & ⊢ (𝜓 ↔ ((𝑥 ⊆ 𝐴 ∧ 𝑟 ⊆ (𝑥 × 𝑥) ∧ 𝑟 We 𝑥) ∧ ω ≼ 𝑥)) & ⊢ ((𝜑 ∧ 𝜓) → 𝐾:∪ 𝑛 ∈ ω (𝑥 ↑𝑚 𝑛)–1-1→𝑥) & ⊢ 𝐷 = (𝐺‘{𝑤 ∈ 𝑥 ∣ ((◡𝐾‘𝑤) ∈ ran 𝐺 ∧ ¬ 𝑤 ∈ (◡𝐺‘(◡𝐾‘𝑤)))}) & ⊢ 𝐹 = (𝑥 ∈ V, 𝑟 ∈ V ↦ if(𝑥 ∈ Fin, (𝐻‘(card‘𝑥)), (𝐷‘∩ {𝑧 ∈ ω ∣ ¬ (𝐷‘𝑧) ∈ 𝑥}))) & ⊢ 𝑊 = {〈𝑎, 𝑠〉 ∣ ((𝑎 ⊆ 𝐴 ∧ 𝑠 ⊆ (𝑎 × 𝑎)) ∧ (𝑠 We 𝑎 ∧ ∀𝑏 ∈ 𝑎 [(◡𝑠 “ {𝑏}) / 𝑣](𝑣𝐹(𝑠 ∩ (𝑣 × 𝑣))) = 𝑏))} & ⊢ 𝑍 = ∪ dom 𝑊 ⇒ ⊢ ¬ 𝜑 | ||
Theorem | pwfseqlem5 9820* |
Lemma for pwfseq 9821. Although in some ways pwfseqlem4 9819 is the "main"
part of the proof, one last aspect which makes up a remark in the
original text is by far the hardest part to formalize. The main proof
relies on the existence of an injection 𝐾 from the set of finite
sequences on an infinite set 𝑥 to 𝑥. Now this alone would
not
be difficult to prove; this is mostly the claim of fseqen 9183. However,
what is needed for the proof is a canonical injection on these
sets,
so we have to start from scratch pulling together explicit bijections
from the lemmas.
If one attempts such a program, it will mostly go through, but there is one key step which is inherently nonconstructive, namely the proof of infxpen 9170. The resolution is not obvious, but it turns out that reversing an infinite ordinal's Cantor normal form absorbs all the non-leading terms (cnfcom3c 8900), which can be used to construct a pairing function explicitly using properties of the ordinal exponential (infxpenc 9174). (Contributed by Mario Carneiro, 31-May-2015.) |
⊢ (𝜑 → 𝐺:𝒫 𝐴–1-1→∪ 𝑛 ∈ ω (𝐴 ↑𝑚 𝑛)) & ⊢ (𝜑 → 𝑋 ⊆ 𝐴) & ⊢ (𝜑 → 𝐻:ω–1-1-onto→𝑋) & ⊢ (𝜓 ↔ ((𝑡 ⊆ 𝐴 ∧ 𝑟 ⊆ (𝑡 × 𝑡) ∧ 𝑟 We 𝑡) ∧ ω ≼ 𝑡)) & ⊢ (𝜑 → ∀𝑏 ∈ (har‘𝒫 𝐴)(ω ⊆ 𝑏 → (𝑁‘𝑏):(𝑏 × 𝑏)–1-1-onto→𝑏)) & ⊢ 𝑂 = OrdIso(𝑟, 𝑡) & ⊢ 𝑇 = (𝑢 ∈ dom 𝑂, 𝑣 ∈ dom 𝑂 ↦ 〈(𝑂‘𝑢), (𝑂‘𝑣)〉) & ⊢ 𝑃 = ((𝑂 ∘ (𝑁‘dom 𝑂)) ∘ ◡𝑇) & ⊢ 𝑆 = seq𝜔((𝑘 ∈ V, 𝑓 ∈ V ↦ (𝑥 ∈ (𝑡 ↑𝑚 suc 𝑘) ↦ ((𝑓‘(𝑥 ↾ 𝑘))𝑃(𝑥‘𝑘)))), {〈∅, (𝑂‘∅)〉}) & ⊢ 𝑄 = (𝑦 ∈ ∪ 𝑛 ∈ ω (𝑡 ↑𝑚 𝑛) ↦ 〈dom 𝑦, ((𝑆‘dom 𝑦)‘𝑦)〉) & ⊢ 𝐼 = (𝑥 ∈ ω, 𝑦 ∈ 𝑡 ↦ 〈(𝑂‘𝑥), 𝑦〉) & ⊢ 𝐾 = ((𝑃 ∘ 𝐼) ∘ 𝑄) ⇒ ⊢ ¬ 𝜑 | ||
Theorem | pwfseq 9821* | The powerset of a Dedekind-infinite set does not inject into the set of finite sequences. The proof is due to Halbeisen and Shelah. Proposition 1.7 of [KanamoriPincus] p. 418. (Contributed by Mario Carneiro, 31-May-2015.) |
⊢ (ω ≼ 𝐴 → ¬ 𝒫 𝐴 ≼ ∪ 𝑛 ∈ ω (𝐴 ↑𝑚 𝑛)) | ||
Theorem | pwxpndom2 9822 | The powerset of a Dedekind-infinite set does not inject into its Cartesian product with itself. (Contributed by Mario Carneiro, 31-May-2015.) (Proof shortened by AV, 18-Jul-2022.) |
⊢ (ω ≼ 𝐴 → ¬ 𝒫 𝐴 ≼ (𝐴 +𝑐 (𝐴 × 𝐴))) | ||
Theorem | pwxpndom 9823 | The powerset of a Dedekind-infinite set does not inject into its Cartesian product with itself. (Contributed by Mario Carneiro, 31-May-2015.) |
⊢ (ω ≼ 𝐴 → ¬ 𝒫 𝐴 ≼ (𝐴 × 𝐴)) | ||
Theorem | pwcdandom 9824 | The powerset of a Dedekind-infinite set does not inject into its cardinal sum with itself. (Contributed by Mario Carneiro, 31-May-2015.) |
⊢ (ω ≼ 𝐴 → ¬ 𝒫 𝐴 ≼ (𝐴 +𝑐 𝐴)) | ||
Theorem | gchcdaidm 9825 | An infinite GCH-set is idempotent under cardinal sum. Part of Lemma 2.2 of [KanamoriPincus] p. 419. (Contributed by Mario Carneiro, 31-May-2015.) |
⊢ ((𝐴 ∈ GCH ∧ ¬ 𝐴 ∈ Fin) → (𝐴 +𝑐 𝐴) ≈ 𝐴) | ||
Theorem | gchxpidm 9826 | An infinite GCH-set is idempotent under cardinal product. Part of Lemma 2.2 of [KanamoriPincus] p. 419. (Contributed by Mario Carneiro, 31-May-2015.) |
⊢ ((𝐴 ∈ GCH ∧ ¬ 𝐴 ∈ Fin) → (𝐴 × 𝐴) ≈ 𝐴) | ||
Theorem | gchpwdom 9827 | A relationship between dominance over the powerset and strict dominance when the sets involved are infinite GCH-sets. Proposition 3.1 of [KanamoriPincus] p. 421. (Contributed by Mario Carneiro, 31-May-2015.) |
⊢ ((ω ≼ 𝐴 ∧ 𝐴 ∈ GCH ∧ 𝐵 ∈ GCH) → (𝐴 ≺ 𝐵 ↔ 𝒫 𝐴 ≼ 𝐵)) | ||
Theorem | gchaleph 9828 | If (ℵ‘𝐴) is a GCH-set and its powerset is well-orderable, then the successor aleph (ℵ‘suc 𝐴) is equinumerous to the powerset of (ℵ‘𝐴). (Contributed by Mario Carneiro, 15-May-2015.) |
⊢ ((𝐴 ∈ On ∧ (ℵ‘𝐴) ∈ GCH ∧ 𝒫 (ℵ‘𝐴) ∈ dom card) → (ℵ‘suc 𝐴) ≈ 𝒫 (ℵ‘𝐴)) | ||
Theorem | gchaleph2 9829 | If (ℵ‘𝐴) and (ℵ‘suc 𝐴) are GCH-sets, then the successor aleph (ℵ‘suc 𝐴) is equinumerous to the powerset of (ℵ‘𝐴). (Contributed by Mario Carneiro, 31-May-2015.) |
⊢ ((𝐴 ∈ On ∧ (ℵ‘𝐴) ∈ GCH ∧ (ℵ‘suc 𝐴) ∈ GCH) → (ℵ‘suc 𝐴) ≈ 𝒫 (ℵ‘𝐴)) | ||
Theorem | hargch 9830 | If 𝐴 + ≈ 𝒫 𝐴, then 𝐴 is a GCH-set. The much simpler converse to gchhar 9836. (Contributed by Mario Carneiro, 2-Jun-2015.) |
⊢ ((har‘𝐴) ≈ 𝒫 𝐴 → 𝐴 ∈ GCH) | ||
Theorem | alephgch 9831 | If (ℵ‘suc 𝐴) is equinumerous to the powerset of (ℵ‘𝐴), then (ℵ‘𝐴) is a GCH-set. (Contributed by Mario Carneiro, 15-May-2015.) |
⊢ ((ℵ‘suc 𝐴) ≈ 𝒫 (ℵ‘𝐴) → (ℵ‘𝐴) ∈ GCH) | ||
Theorem | gch2 9832 | It is sufficient to require that all alephs are GCH-sets to ensure the full generalized continuum hypothesis. (The proof uses the Axiom of Regularity.) (Contributed by Mario Carneiro, 15-May-2015.) |
⊢ (GCH = V ↔ ran ℵ ⊆ GCH) | ||
Theorem | gch3 9833 | An equivalent formulation of the generalized continuum hypothesis. (Contributed by Mario Carneiro, 15-May-2015.) |
⊢ (GCH = V ↔ ∀𝑥 ∈ On (ℵ‘suc 𝑥) ≈ 𝒫 (ℵ‘𝑥)) | ||
Theorem | gch-kn 9834* | The equivalence of two versions of the Generalized Continuum Hypothesis. The right-hand side is the standard version in the literature. The left-hand side is a version devised by Kannan Nambiar, which he calls the Axiom of Combinatorial Sets. For the notation and motivation behind this axiom, see his paper, "Derivation of Continuum Hypothesis from Axiom of Combinatorial Sets", available at http://www.e-atheneum.net/science/derivation_ch.pdf. The equivalence of the two sides provides a negative answer to Open Problem 2 in http://www.e-atheneum.net/science/open_problem_print.pdf. The key idea in the proof below is to equate both sides of alephexp2 9738 to the successor aleph using enen2 8389. (Contributed by NM, 1-Oct-2004.) |
⊢ (𝐴 ∈ On → ((ℵ‘suc 𝐴) ≈ {𝑥 ∣ (𝑥 ⊆ (ℵ‘𝐴) ∧ 𝑥 ≈ (ℵ‘𝐴))} ↔ (ℵ‘suc 𝐴) ≈ (2o ↑𝑚 (ℵ‘𝐴)))) | ||
Theorem | gchaclem 9835 | Lemma for gchac 9838 (obsolete, used in Sierpiński's proof). (Contributed by Mario Carneiro, 15-May-2015.) |
⊢ (𝜑 → ω ≼ 𝐴) & ⊢ (𝜑 → 𝒫 𝐶 ∈ GCH) & ⊢ (𝜑 → (𝐴 ≼ 𝐶 ∧ (𝐵 ≼ 𝒫 𝐶 → 𝒫 𝐴 ≼ 𝐵))) ⇒ ⊢ (𝜑 → (𝐴 ≼ 𝒫 𝐶 ∧ (𝐵 ≼ 𝒫 𝒫 𝐶 → 𝒫 𝐴 ≼ 𝐵))) | ||
Theorem | gchhar 9836 | A "local" form of gchac 9838. If 𝐴 and 𝒫 𝐴 are GCH-sets, then the Hartogs number of 𝐴 is 𝒫 𝐴 (so 𝒫 𝐴 and a fortiori 𝐴 are well-orderable). The proof is due to Specker. Theorem 2.1 of [KanamoriPincus] p. 419. (Contributed by Mario Carneiro, 31-May-2015.) |
⊢ ((ω ≼ 𝐴 ∧ 𝐴 ∈ GCH ∧ 𝒫 𝐴 ∈ GCH) → (har‘𝐴) ≈ 𝒫 𝐴) | ||
Theorem | gchacg 9837 | A "local" form of gchac 9838. If 𝐴 and 𝒫 𝐴 are GCH-sets, then 𝒫 𝐴 is well-orderable. The proof is due to Specker. Theorem 2.1 of [KanamoriPincus] p. 419. (Contributed by Mario Carneiro, 15-May-2015.) |
⊢ ((ω ≼ 𝐴 ∧ 𝐴 ∈ GCH ∧ 𝒫 𝐴 ∈ GCH) → 𝒫 𝐴 ∈ dom card) | ||
Theorem | gchac 9838 | The Generalized Continuum Hypothesis implies the Axiom of Choice. The original proof is due to Sierpiński (1947); we use a refinement of Sierpiński's result due to Specker. (Contributed by Mario Carneiro, 15-May-2015.) |
⊢ (GCH = V → CHOICE) | ||
Here we introduce Tarski-Grothendieck (TG) set theory, named after mathematicians Alfred Tarski and Alexander Grothendieck. TG theory extends ZFC with the TG Axiom ax-groth 9980, which states that for every set 𝑥 there is an inaccessible cardinal 𝑦 such that 𝑦 is not in 𝑥. The addition of this axiom to ZFC set theory provides a framework for category theory, thus for all practical purposes giving us a complete foundation for "all of mathematics." We first introduce the concept of inaccessibles, including weakly and strongly inaccessible cardinals (df-wina 9841 and df-ina 9842 respectively ), Tarski classes (df-tsk 9906), and Grothendieck universes (df-gru 9948). We then introduce the Tarski's axiom ax-groth 9980 and prove various properties from that. | ||
Syntax | cwina 9839 | The class of weak inaccessibles. |
class Inaccw | ||
Syntax | cina 9840 | The class of strong inaccessibles. |
class Inacc | ||
Definition | df-wina 9841* | An ordinal is weakly inaccessible iff it is a regular limit cardinal. Note that our definition allows ω as a weakly inaccessible cardinal. (Contributed by Mario Carneiro, 22-Jun-2013.) |
⊢ Inaccw = {𝑥 ∣ (𝑥 ≠ ∅ ∧ (cf‘𝑥) = 𝑥 ∧ ∀𝑦 ∈ 𝑥 ∃𝑧 ∈ 𝑥 𝑦 ≺ 𝑧)} | ||
Definition | df-ina 9842* | An ordinal is strongly inaccessible iff it is a regular strong limit cardinal, which is to say that it dominates the powersets of every smaller ordinal. (Contributed by Mario Carneiro, 22-Jun-2013.) |
⊢ Inacc = {𝑥 ∣ (𝑥 ≠ ∅ ∧ (cf‘𝑥) = 𝑥 ∧ ∀𝑦 ∈ 𝑥 𝒫 𝑦 ≺ 𝑥)} | ||
Theorem | elwina 9843* | Conditions of weak inaccessibility. (Contributed by Mario Carneiro, 22-Jun-2013.) |
⊢ (𝐴 ∈ Inaccw ↔ (𝐴 ≠ ∅ ∧ (cf‘𝐴) = 𝐴 ∧ ∀𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐴 𝑥 ≺ 𝑦)) | ||
Theorem | elina 9844* | Conditions of strong inaccessibility. (Contributed by Mario Carneiro, 22-Jun-2013.) |
⊢ (𝐴 ∈ Inacc ↔ (𝐴 ≠ ∅ ∧ (cf‘𝐴) = 𝐴 ∧ ∀𝑥 ∈ 𝐴 𝒫 𝑥 ≺ 𝐴)) | ||
Theorem | winaon 9845 | A weakly inaccessible cardinal is an ordinal. (Contributed by Mario Carneiro, 29-May-2014.) |
⊢ (𝐴 ∈ Inaccw → 𝐴 ∈ On) | ||
Theorem | inawinalem 9846* | Lemma for inawina 9847. (Contributed by Mario Carneiro, 8-Jun-2014.) |
⊢ (𝐴 ∈ On → (∀𝑥 ∈ 𝐴 𝒫 𝑥 ≺ 𝐴 → ∀𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐴 𝑥 ≺ 𝑦)) | ||
Theorem | inawina 9847 | Every strongly inaccessible cardinal is weakly inaccessible. (Contributed by Mario Carneiro, 29-May-2014.) |
⊢ (𝐴 ∈ Inacc → 𝐴 ∈ Inaccw) | ||
Theorem | omina 9848 | ω is a strongly inaccessible cardinal. (Many definitions of "inaccessible" explicitly disallow ω as an inaccessible cardinal, but this choice allows us to reuse our results for inaccessibles for ω.) (Contributed by Mario Carneiro, 29-May-2014.) |
⊢ ω ∈ Inacc | ||
Theorem | winacard 9849 | A weakly inaccessible cardinal is a cardinal. (Contributed by Mario Carneiro, 29-May-2014.) |
⊢ (𝐴 ∈ Inaccw → (card‘𝐴) = 𝐴) | ||
Theorem | winainflem 9850* | A weakly inaccessible cardinal is infinite. (Contributed by Mario Carneiro, 29-May-2014.) |
⊢ ((𝐴 ≠ ∅ ∧ 𝐴 ∈ On ∧ ∀𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐴 𝑥 ≺ 𝑦) → ω ⊆ 𝐴) | ||
Theorem | winainf 9851 | A weakly inaccessible cardinal is infinite. (Contributed by Mario Carneiro, 29-May-2014.) |
⊢ (𝐴 ∈ Inaccw → ω ⊆ 𝐴) | ||
Theorem | winalim 9852 | A weakly inaccessible cardinal is a limit ordinal. (Contributed by Mario Carneiro, 29-May-2014.) |
⊢ (𝐴 ∈ Inaccw → Lim 𝐴) | ||
Theorem | winalim2 9853* | A nontrivial weakly inaccessible cardinal is a limit aleph. (Contributed by Mario Carneiro, 29-May-2014.) |
⊢ ((𝐴 ∈ Inaccw ∧ 𝐴 ≠ ω) → ∃𝑥((ℵ‘𝑥) = 𝐴 ∧ Lim 𝑥)) | ||
Theorem | winafp 9854 | A nontrivial weakly inaccessible cardinal is a fixed point of the aleph function. (Contributed by Mario Carneiro, 29-May-2014.) |
⊢ ((𝐴 ∈ Inaccw ∧ 𝐴 ≠ ω) → (ℵ‘𝐴) = 𝐴) | ||
Theorem | winafpi 9855 | This theorem, which states that a nontrivial inaccessible cardinal is its own aleph number, is stated here in inference form, where the assumptions are in the hypotheses rather than an antecedent. Often, we use dedth 4363 to turn this type of statement into the closed form statement winafp 9854, but in this case, since it is consistent with ZFC that there are no nontrivial inaccessible cardinals, it is not possible to prove winafp 9854 using this theorem and dedth 4363, in ZFC. (You can prove this if you use ax-groth 9980, though.) (Contributed by Mario Carneiro, 28-May-2014.) |
⊢ 𝐴 ∈ Inaccw & ⊢ 𝐴 ≠ ω ⇒ ⊢ (ℵ‘𝐴) = 𝐴 | ||
Theorem | gchina 9856 | Assuming the GCH, weakly and strongly inaccessible cardinals coincide. Theorem 11.20 of [TakeutiZaring] p. 106. (Contributed by Mario Carneiro, 5-Jun-2015.) |
⊢ (GCH = V → Inaccw = Inacc) | ||
Syntax | cwun 9857 | Extend class definition to include the class of all weak universes. |
class WUni | ||
Syntax | cwunm 9858 | Extend class definition to include the map whose value is the smallest weak universe of which the given set is a subset. |
class wUniCl | ||
Definition | df-wun 9859* | The class of all weak universes. A weak universe is a nonempty transitive class closed under union, pairing, and powerset. The advantage of weak universes over Grothendieck universes is that one can prove that every set is contained in a weak universe in ZF (see uniwun 9897) whereas the analogue for Grothendieck universes requires ax-groth 9980 (see grothtsk 9992). (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ WUni = {𝑢 ∣ (Tr 𝑢 ∧ 𝑢 ≠ ∅ ∧ ∀𝑥 ∈ 𝑢 (∪ 𝑥 ∈ 𝑢 ∧ 𝒫 𝑥 ∈ 𝑢 ∧ ∀𝑦 ∈ 𝑢 {𝑥, 𝑦} ∈ 𝑢))} | ||
Definition | df-wunc 9860* | A function that maps a set 𝑥 to the smallest weak universe that contains the elements of the set. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ wUniCl = (𝑥 ∈ V ↦ ∩ {𝑢 ∈ WUni ∣ 𝑥 ⊆ 𝑢}) | ||
Theorem | iswun 9861* | Properties of a weak universe. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝑈 ∈ 𝑉 → (𝑈 ∈ WUni ↔ (Tr 𝑈 ∧ 𝑈 ≠ ∅ ∧ ∀𝑥 ∈ 𝑈 (∪ 𝑥 ∈ 𝑈 ∧ 𝒫 𝑥 ∈ 𝑈 ∧ ∀𝑦 ∈ 𝑈 {𝑥, 𝑦} ∈ 𝑈)))) | ||
Theorem | wuntr 9862 | A weak universe is transitive. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝑈 ∈ WUni → Tr 𝑈) | ||
Theorem | wununi 9863 | A weak universe is closed under union. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) ⇒ ⊢ (𝜑 → ∪ 𝐴 ∈ 𝑈) | ||
Theorem | wunpw 9864 | A weak universe is closed under powerset. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) ⇒ ⊢ (𝜑 → 𝒫 𝐴 ∈ 𝑈) | ||
Theorem | wunelss 9865 | The elements of a weak universe are also subsets of it. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) ⇒ ⊢ (𝜑 → 𝐴 ⊆ 𝑈) | ||
Theorem | wunpr 9866 | A weak universe is closed under pairing. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) & ⊢ (𝜑 → 𝐵 ∈ 𝑈) ⇒ ⊢ (𝜑 → {𝐴, 𝐵} ∈ 𝑈) | ||
Theorem | wunun 9867 | A weak universe is closed under binary union. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) & ⊢ (𝜑 → 𝐵 ∈ 𝑈) ⇒ ⊢ (𝜑 → (𝐴 ∪ 𝐵) ∈ 𝑈) | ||
Theorem | wuntp 9868 | A weak universe is closed under unordered triple. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) & ⊢ (𝜑 → 𝐵 ∈ 𝑈) & ⊢ (𝜑 → 𝐶 ∈ 𝑈) ⇒ ⊢ (𝜑 → {𝐴, 𝐵, 𝐶} ∈ 𝑈) | ||
Theorem | wunss 9869 | A weak universe is closed under subsets. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) & ⊢ (𝜑 → 𝐵 ⊆ 𝐴) ⇒ ⊢ (𝜑 → 𝐵 ∈ 𝑈) | ||
Theorem | wunin 9870 | A weak universe is closed under binary intersections. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) ⇒ ⊢ (𝜑 → (𝐴 ∩ 𝐵) ∈ 𝑈) | ||
Theorem | wundif 9871 | A weak universe is closed under class difference. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) ⇒ ⊢ (𝜑 → (𝐴 ∖ 𝐵) ∈ 𝑈) | ||
Theorem | wunint 9872 | A weak universe is closed under nonempty intersections. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) ⇒ ⊢ ((𝜑 ∧ 𝐴 ≠ ∅) → ∩ 𝐴 ∈ 𝑈) | ||
Theorem | wunsn 9873 | A weak universe is closed under singletons. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) ⇒ ⊢ (𝜑 → {𝐴} ∈ 𝑈) | ||
Theorem | wunsuc 9874 | A weak universe is closed under successors. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) ⇒ ⊢ (𝜑 → suc 𝐴 ∈ 𝑈) | ||
Theorem | wun0 9875 | A weak universe contains the empty set. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) ⇒ ⊢ (𝜑 → ∅ ∈ 𝑈) | ||
Theorem | wunr1om 9876 | A weak universe is infinite, because it contains all the finite levels of the cumulative hierarchy. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) ⇒ ⊢ (𝜑 → (𝑅1 “ ω) ⊆ 𝑈) | ||
Theorem | wunom 9877 | A weak universe contains all the finite ordinals, and hence is infinite. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) ⇒ ⊢ (𝜑 → ω ⊆ 𝑈) | ||
Theorem | wunfi 9878 | A weak universe contains all finite sets with elements drawn from the universe. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ⊆ 𝑈) & ⊢ (𝜑 → 𝐴 ∈ Fin) ⇒ ⊢ (𝜑 → 𝐴 ∈ 𝑈) | ||
Theorem | wunop 9879 | A weak universe is closed under ordered pairs. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) & ⊢ (𝜑 → 𝐵 ∈ 𝑈) ⇒ ⊢ (𝜑 → 〈𝐴, 𝐵〉 ∈ 𝑈) | ||
Theorem | wunot 9880 | A weak universe is closed under ordered triples. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) & ⊢ (𝜑 → 𝐵 ∈ 𝑈) & ⊢ (𝜑 → 𝐶 ∈ 𝑈) ⇒ ⊢ (𝜑 → 〈𝐴, 𝐵, 𝐶〉 ∈ 𝑈) | ||
Theorem | wunxp 9881 | A weak universe is closed under cartesian products. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) & ⊢ (𝜑 → 𝐵 ∈ 𝑈) ⇒ ⊢ (𝜑 → (𝐴 × 𝐵) ∈ 𝑈) | ||
Theorem | wunpm 9882 | A weak universe is closed under partial mappings. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) & ⊢ (𝜑 → 𝐵 ∈ 𝑈) ⇒ ⊢ (𝜑 → (𝐴 ↑pm 𝐵) ∈ 𝑈) | ||
Theorem | wunmap 9883 | A weak universe is closed under mappings. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) & ⊢ (𝜑 → 𝐵 ∈ 𝑈) ⇒ ⊢ (𝜑 → (𝐴 ↑𝑚 𝐵) ∈ 𝑈) | ||
Theorem | wunf 9884 | A weak universe is closed under functions with known domain and codomain. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) & ⊢ (𝜑 → 𝐵 ∈ 𝑈) & ⊢ (𝜑 → 𝐹:𝐴⟶𝐵) ⇒ ⊢ (𝜑 → 𝐹 ∈ 𝑈) | ||
Theorem | wundm 9885 | A weak universe is closed under the domain operator. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) ⇒ ⊢ (𝜑 → dom 𝐴 ∈ 𝑈) | ||
Theorem | wunrn 9886 | A weak universe is closed under the range operator. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) ⇒ ⊢ (𝜑 → ran 𝐴 ∈ 𝑈) | ||
Theorem | wuncnv 9887 | A weak universe is closed under the converse operator. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) ⇒ ⊢ (𝜑 → ◡𝐴 ∈ 𝑈) | ||
Theorem | wunres 9888 | A weak universe is closed under restrictions. (Contributed by Mario Carneiro, 12-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) ⇒ ⊢ (𝜑 → (𝐴 ↾ 𝐵) ∈ 𝑈) | ||
Theorem | wunfv 9889 | A weak universe is closed under the function value operator. (Contributed by Mario Carneiro, 3-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) ⇒ ⊢ (𝜑 → (𝐴‘𝐵) ∈ 𝑈) | ||
Theorem | wunco 9890 | A weak universe is closed under composition. (Contributed by Mario Carneiro, 12-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) & ⊢ (𝜑 → 𝐵 ∈ 𝑈) ⇒ ⊢ (𝜑 → (𝐴 ∘ 𝐵) ∈ 𝑈) | ||
Theorem | wuntpos 9891 | A weak universe is closed under transposition. (Contributed by Mario Carneiro, 12-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) ⇒ ⊢ (𝜑 → tpos 𝐴 ∈ 𝑈) | ||
Theorem | intwun 9892 | The intersection of a collection of weak universes is a weak universe. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ ((𝐴 ⊆ WUni ∧ 𝐴 ≠ ∅) → ∩ 𝐴 ∈ WUni) | ||
Theorem | r1limwun 9893 | Each limit stage in the cumulative hierarchy is a weak universe. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ ((𝐴 ∈ 𝑉 ∧ Lim 𝐴) → (𝑅1‘𝐴) ∈ WUni) | ||
Theorem | r1wunlim 9894 | The weak universes in the cumulative hierarchy are exactly the limit ordinals. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝐴 ∈ 𝑉 → ((𝑅1‘𝐴) ∈ WUni ↔ Lim 𝐴)) | ||
Theorem | wunex2 9895* | Construct a weak universe from a given set. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ 𝐹 = (rec((𝑧 ∈ V ↦ ((𝑧 ∪ ∪ 𝑧) ∪ ∪ 𝑥 ∈ 𝑧 ({𝒫 𝑥, ∪ 𝑥} ∪ ran (𝑦 ∈ 𝑧 ↦ {𝑥, 𝑦})))), (𝐴 ∪ 1o)) ↾ ω) & ⊢ 𝑈 = ∪ ran 𝐹 ⇒ ⊢ (𝐴 ∈ 𝑉 → (𝑈 ∈ WUni ∧ 𝐴 ⊆ 𝑈)) | ||
Theorem | wunex 9896* | Construct a weak universe from a given set. See also wunex2 9895. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝐴 ∈ 𝑉 → ∃𝑢 ∈ WUni 𝐴 ⊆ 𝑢) | ||
Theorem | uniwun 9897 | Every set is contained in a weak universe. This is the analogue of grothtsk 9992 for weak universes, but it is provable in ZF without the Tarski-Grothendieck axiom, contrary to grothtsk 9992. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ ∪ WUni = V | ||
Theorem | wunex3 9898 | Construct a weak universe from a given set. This version of wunex 9896 has a simpler proof, but requires the axiom of regularity. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ 𝑈 = (𝑅1‘((rank‘𝐴) +o ω)) ⇒ ⊢ (𝐴 ∈ 𝑉 → (𝑈 ∈ WUni ∧ 𝐴 ⊆ 𝑈)) | ||
Theorem | wuncval 9899* | Value of the weak universe closure operator. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝐴 ∈ 𝑉 → (wUniCl‘𝐴) = ∩ {𝑢 ∈ WUni ∣ 𝐴 ⊆ 𝑢}) | ||
Theorem | wuncid 9900 | The weak universe closure of a set contains the set. (Contributed by Mario Carneiro, 2-Jan-2017.) |
⊢ (𝐴 ∈ 𝑉 → 𝐴 ⊆ (wUniCl‘𝐴)) |
< Previous Next > |
Copyright terms: Public domain | < Previous Next > |