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Type | Label | Description |
---|---|---|
Statement | ||
Theorem | rexcom4f 28701* | Commutation of restricted and unrestricted existential quantifiers. (Contributed by NM, 12-Apr-2004.) (Proof shortened by Andrew Salmon, 8-Jun-2011.) (Revised by Thierry Arnoux, 8-Mar-2017.) |
⊢ Ⅎ𝑦𝐴 ⇒ ⊢ (∃𝑥 ∈ 𝐴 ∃𝑦𝜑 ↔ ∃𝑦∃𝑥 ∈ 𝐴 𝜑) | ||
Theorem | 19.9d2rf 28702 | A deduction version of one direction of 19.9 2060 with two variables. (Contributed by Thierry Arnoux, 20-Mar-2017.) |
⊢ Ⅎ𝑦𝜑 & ⊢ (𝜑 → Ⅎ𝑥𝜓) & ⊢ (𝜑 → Ⅎ𝑦𝜓) & ⊢ (𝜑 → ∃𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜓) ⇒ ⊢ (𝜑 → 𝜓) | ||
Theorem | 19.9d2r 28703* | A deduction version of one direction of 19.9 2060 with two variables. (Contributed by Thierry Arnoux, 30-Jan-2017.) |
⊢ (𝜑 → Ⅎ𝑥𝜓) & ⊢ (𝜑 → Ⅎ𝑦𝜓) & ⊢ (𝜑 → ∃𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜓) ⇒ ⊢ (𝜑 → 𝜓) | ||
Theorem | clelsb3f 28704 | Substitution applied to an atomic wff (class version of elsb3 2422). (Contributed by Rodolfo Medina, 28-Apr-2010.) (Proof shortened by Andrew Salmon, 14-Jun-2011.) (Revised by Thierry Arnoux, 13-Mar-2017.) |
⊢ Ⅎ𝑦𝐴 ⇒ ⊢ ([𝑥 / 𝑦]𝑦 ∈ 𝐴 ↔ 𝑥 ∈ 𝐴) | ||
Theorem | sbceqbidf 28705 | Equality theorem for class substitution. (Contributed by Thierry Arnoux, 4-Sep-2018.) |
⊢ Ⅎ𝑥𝜑 & ⊢ (𝜑 → 𝐴 = 𝐵) & ⊢ (𝜑 → (𝜓 ↔ 𝜒)) ⇒ ⊢ (𝜑 → ([𝐴 / 𝑥]𝜓 ↔ [𝐵 / 𝑥]𝜒)) | ||
Theorem | sbcies 28706* | A special version of class substitution commonly used for structures. (Contributed by Thierry Arnoux, 14-Mar-2019.) |
⊢ 𝐴 = (𝐸‘𝑊) & ⊢ (𝑎 = 𝐴 → (𝜑 ↔ 𝜓)) ⇒ ⊢ (𝑤 = 𝑊 → ([(𝐸‘𝑤) / 𝑎]𝜓 ↔ 𝜑)) | ||
Theorem | moel 28707* | "At most one" element in a set. (Contributed by Thierry Arnoux, 26-Jul-2018.) |
⊢ (∃*𝑥 𝑥 ∈ 𝐴 ↔ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 𝑥 = 𝑦) | ||
Theorem | mo5f 28708* | Alternate definition of "at most one." (Contributed by Thierry Arnoux, 1-Mar-2017.) |
⊢ Ⅎ𝑖𝜑 & ⊢ Ⅎ𝑗𝜑 ⇒ ⊢ (∃*𝑥𝜑 ↔ ∀𝑖∀𝑗(([𝑖 / 𝑥]𝜑 ∧ [𝑗 / 𝑥]𝜑) → 𝑖 = 𝑗)) | ||
Theorem | nmo 28709* | Negation of "at most one". (Contributed by Thierry Arnoux, 26-Feb-2017.) |
⊢ Ⅎ𝑦𝜑 ⇒ ⊢ (¬ ∃*𝑥𝜑 ↔ ∀𝑦∃𝑥(𝜑 ∧ 𝑥 ≠ 𝑦)) | ||
Theorem | moimd 28710* | "At most one" is preserved through implication (notice wff reversal). (Contributed by Thierry Arnoux, 25-Feb-2017.) |
⊢ (𝜑 → (𝜓 → 𝜒)) ⇒ ⊢ (𝜑 → (∃*𝑥𝜒 → ∃*𝑥𝜓)) | ||
Theorem | rmoeqALT 28711* | Equality's restricted existential "at most one" property. (Contributed by Thierry Arnoux, 30-Mar-2018.) Obsolete version of rmoeq 3372 as of 27-Oct-2020. (New usage is discouraged.) (Proof modification is discouraged.) |
⊢ (𝐴 ∈ 𝑉 → ∃*𝑥 ∈ 𝐵 𝑥 = 𝐴) | ||
Theorem | 2reuswap2 28712* | A condition allowing swap of uniqueness and existential quantifiers. (Contributed by Thierry Arnoux, 7-Apr-2017.) |
⊢ (∀𝑥 ∈ 𝐴 ∃*𝑦(𝑦 ∈ 𝐵 ∧ 𝜑) → (∃!𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜑 → ∃!𝑦 ∈ 𝐵 ∃𝑥 ∈ 𝐴 𝜑)) | ||
Theorem | reuxfr3d 28713* | Transfer existential uniqueness from a variable 𝑥 to another variable 𝑦 contained in expression 𝐴. Cf. reuxfr2d 4817. (Contributed by Thierry Arnoux, 7-Apr-2017.) (Revised by Thierry Arnoux, 8-Oct-2017.) |
⊢ ((𝜑 ∧ 𝑦 ∈ 𝐶) → 𝐴 ∈ 𝐵) & ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐵) → ∃*𝑦 ∈ 𝐶 𝑥 = 𝐴) ⇒ ⊢ (𝜑 → (∃!𝑥 ∈ 𝐵 ∃𝑦 ∈ 𝐶 (𝑥 = 𝐴 ∧ 𝜓) ↔ ∃!𝑦 ∈ 𝐶 𝜓)) | ||
Theorem | reuxfr4d 28714* | Transfer existential uniqueness from a variable 𝑥 to another variable 𝑦 contained in expression 𝐴. Cf. reuxfrd 4819. (Contributed by Thierry Arnoux, 7-Apr-2017.) |
⊢ ((𝜑 ∧ 𝑦 ∈ 𝐶) → 𝐴 ∈ 𝐵) & ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐵) → ∃!𝑦 ∈ 𝐶 𝑥 = 𝐴) & ⊢ ((𝜑 ∧ 𝑥 = 𝐴) → (𝜓 ↔ 𝜒)) ⇒ ⊢ (𝜑 → (∃!𝑥 ∈ 𝐵 𝜓 ↔ ∃!𝑦 ∈ 𝐶 𝜒)) | ||
Theorem | rexunirn 28715* | Restricted existential quantification over the union of the range of a function. Cf. rexrn 6269 and eluni2 4376. (Contributed by Thierry Arnoux, 19-Sep-2017.) |
⊢ 𝐹 = (𝑥 ∈ 𝐴 ↦ 𝐵) & ⊢ (𝑥 ∈ 𝐴 → 𝐵 ∈ 𝑉) ⇒ ⊢ (∃𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜑 → ∃𝑦 ∈ ∪ ran 𝐹𝜑) | ||
Theorem | rmoxfrdOLD 28716* | Transfer "at most one" restricted quantification from a variable 𝑥 to another variable 𝑦 contained in expression 𝐴. (Contributed by Thierry Arnoux, 7-Apr-2017.) (New usage is discouraged.) (Proof modification is discouraged.) |
⊢ ((𝜑 ∧ 𝑦 ∈ 𝐶) → 𝐴 ∈ 𝐵) & ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐵) → ∃!𝑦 ∈ 𝐶 𝑥 = 𝐴) & ⊢ ((𝜑 ∧ 𝑥 = 𝐴) → (𝜓 ↔ 𝜒)) ⇒ ⊢ (𝜑 → (∃*𝑥(𝑥 ∈ 𝐵 ∧ 𝜓) ↔ ∃*𝑦(𝑦 ∈ 𝐶 ∧ 𝜒))) | ||
Theorem | rmoxfrd 28717* | Transfer "at most one" restricted quantification from a variable 𝑥 to another variable 𝑦 contained in expression 𝐴. (Contributed by Thierry Arnoux, 7-Apr-2017.) (Revised by Thierry Arnoux, 8-Oct-2017.) |
⊢ ((𝜑 ∧ 𝑦 ∈ 𝐶) → 𝐴 ∈ 𝐵) & ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐵) → ∃!𝑦 ∈ 𝐶 𝑥 = 𝐴) & ⊢ ((𝜑 ∧ 𝑥 = 𝐴) → (𝜓 ↔ 𝜒)) ⇒ ⊢ (𝜑 → (∃*𝑥 ∈ 𝐵 𝜓 ↔ ∃*𝑦 ∈ 𝐶 𝜒)) | ||
Theorem | ssrmo 28718 | "At most one" existential quantification restricted to a subclass. (Contributed by Thierry Arnoux, 8-Oct-2017.) |
⊢ Ⅎ𝑥𝐴 & ⊢ Ⅎ𝑥𝐵 ⇒ ⊢ (𝐴 ⊆ 𝐵 → (∃*𝑥 ∈ 𝐵 𝜑 → ∃*𝑥 ∈ 𝐴 𝜑)) | ||
Theorem | rmo3f 28719* | Restricted "at most one" using explicit substitution. (Contributed by NM, 4-Nov-2012.) (Revised by NM, 16-Jun-2017.) (Revised by Thierry Arnoux, 8-Oct-2017.) |
⊢ Ⅎ𝑥𝐴 & ⊢ Ⅎ𝑦𝐴 & ⊢ Ⅎ𝑦𝜑 ⇒ ⊢ (∃*𝑥 ∈ 𝐴 𝜑 ↔ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 ((𝜑 ∧ [𝑦 / 𝑥]𝜑) → 𝑥 = 𝑦)) | ||
Theorem | rmo4fOLD 28720* | Restricted "at most one" using implicit substitution. (Contributed by NM, 24-Oct-2006.) (Revised by Thierry Arnoux, 11-Oct-2016.) (Revised by Thierry Arnoux, 8-Mar-2017.) (New usage is discouraged.) (Proof modification is discouraged.) |
⊢ Ⅎ𝑥𝐴 & ⊢ Ⅎ𝑦𝐴 & ⊢ Ⅎ𝑥𝜓 & ⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜓)) ⇒ ⊢ (∃*𝑥(𝑥 ∈ 𝐴 ∧ 𝜑) ↔ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 ((𝜑 ∧ 𝜓) → 𝑥 = 𝑦)) | ||
Theorem | rmo4f 28721* | Restricted "at most one" using implicit substitution. (Contributed by NM, 24-Oct-2006.) (Revised by Thierry Arnoux, 11-Oct-2016.) (Revised by Thierry Arnoux, 8-Mar-2017.) (Revised by Thierry Arnoux, 8-Oct-2017.) |
⊢ Ⅎ𝑥𝐴 & ⊢ Ⅎ𝑦𝐴 & ⊢ Ⅎ𝑥𝜓 & ⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜓)) ⇒ ⊢ (∃*𝑥 ∈ 𝐴 𝜑 ↔ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 ((𝜑 ∧ 𝜓) → 𝑥 = 𝑦)) | ||
Theorem | rabrab 28722 | Abstract builder restricted to another restricted abstract builder. (Contributed by Thierry Arnoux, 30-Aug-2017.) |
⊢ {𝑥 ∈ {𝑥 ∈ 𝐴 ∣ 𝜑} ∣ 𝜓} = {𝑥 ∈ 𝐴 ∣ (𝜑 ∧ 𝜓)} | ||
Theorem | rabtru 28723 | Abtract builder using the constant wff ⊤ (Contributed by Thierry Arnoux, 4-May-2020.) |
⊢ Ⅎ𝑥𝐴 ⇒ ⊢ {𝑥 ∈ 𝐴 ∣ ⊤} = 𝐴 | ||
Theorem | rabid2f 28724 | An "identity" law for restricted class abstraction. (Contributed by NM, 9-Oct-2003.) (Proof shortened by Andrew Salmon, 30-May-2011.) (Revised by Thierry Arnoux, 13-Mar-2017.) |
⊢ Ⅎ𝑥𝐴 ⇒ ⊢ (𝐴 = {𝑥 ∈ 𝐴 ∣ 𝜑} ↔ ∀𝑥 ∈ 𝐴 𝜑) | ||
Theorem | rabexgfGS 28725 | Separation Scheme in terms of a restricted class abstraction. To be removed in profit of Glauco's equivalent version. (Contributed by Thierry Arnoux, 11-May-2017.) |
⊢ Ⅎ𝑥𝐴 ⇒ ⊢ (𝐴 ∈ 𝑉 → {𝑥 ∈ 𝐴 ∣ 𝜑} ∈ V) | ||
Theorem | rabsnel 28726* | Truth implied by equality of a restricted class abstraction and a singleton. (Contributed by Thierry Arnoux, 15-Sep-2018.) |
⊢ 𝐵 ∈ V ⇒ ⊢ ({𝑥 ∈ 𝐴 ∣ 𝜑} = {𝐵} → 𝐵 ∈ 𝐴) | ||
Theorem | foresf1o 28727* | From a surjective function, *choose* a subset of the domain, such that the restricted function is bijective. (Contributed by Thierry Arnoux, 27-Jan-2020.) |
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐹:𝐴–onto→𝐵) → ∃𝑥 ∈ 𝒫 𝐴(𝐹 ↾ 𝑥):𝑥–1-1-onto→𝐵) | ||
Theorem | rabfodom 28728* | Domination relation for restricted abstract class builders, based on a surjective function. (Contributed by Thierry Arnoux, 27-Jan-2020.) |
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴 ∧ 𝑦 = (𝐹‘𝑥)) → (𝜒 ↔ 𝜓)) & ⊢ (𝜑 → 𝐴 ∈ 𝑉) & ⊢ (𝜑 → 𝐹:𝐴–onto→𝐵) ⇒ ⊢ (𝜑 → {𝑦 ∈ 𝐵 ∣ 𝜒} ≼ {𝑥 ∈ 𝐴 ∣ 𝜓}) | ||
Theorem | abrexdomjm 28729* | An indexed set is dominated by the indexing set. (Contributed by Jeff Madsen, 2-Sep-2009.) |
⊢ (𝑦 ∈ 𝐴 → ∃*𝑥𝜑) ⇒ ⊢ (𝐴 ∈ 𝑉 → {𝑥 ∣ ∃𝑦 ∈ 𝐴 𝜑} ≼ 𝐴) | ||
Theorem | abrexdom2jm 28730* | An indexed set is dominated by the indexing set. (Contributed by Jeff Madsen, 2-Sep-2009.) |
⊢ (𝐴 ∈ 𝑉 → {𝑥 ∣ ∃𝑦 ∈ 𝐴 𝑥 = 𝐵} ≼ 𝐴) | ||
Theorem | abrexexd 28731* | Existence of a class abstraction of existentially restricted sets. (Contributed by Thierry Arnoux, 10-May-2017.) |
⊢ Ⅎ𝑥𝐴 & ⊢ (𝜑 → 𝐴 ∈ V) ⇒ ⊢ (𝜑 → {𝑦 ∣ ∃𝑥 ∈ 𝐴 𝑦 = 𝐵} ∈ V) | ||
Theorem | elabreximd 28732* | Class substitution in an image set. (Contributed by Thierry Arnoux, 30-Dec-2016.) |
⊢ Ⅎ𝑥𝜑 & ⊢ Ⅎ𝑥𝜒 & ⊢ (𝐴 = 𝐵 → (𝜒 ↔ 𝜓)) & ⊢ (𝜑 → 𝐴 ∈ 𝑉) & ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐶) → 𝜓) ⇒ ⊢ ((𝜑 ∧ 𝐴 ∈ {𝑦 ∣ ∃𝑥 ∈ 𝐶 𝑦 = 𝐵}) → 𝜒) | ||
Theorem | elabreximdv 28733* | Class substitution in an image set. (Contributed by Thierry Arnoux, 30-Dec-2016.) |
⊢ (𝐴 = 𝐵 → (𝜒 ↔ 𝜓)) & ⊢ (𝜑 → 𝐴 ∈ 𝑉) & ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐶) → 𝜓) ⇒ ⊢ ((𝜑 ∧ 𝐴 ∈ {𝑦 ∣ ∃𝑥 ∈ 𝐶 𝑦 = 𝐵}) → 𝜒) | ||
Theorem | abrexss 28734* | A necessary condition for an image set to be a subset. (Contributed by Thierry Arnoux, 6-Feb-2017.) |
⊢ Ⅎ𝑥𝐶 ⇒ ⊢ (∀𝑥 ∈ 𝐴 𝐵 ∈ 𝐶 → {𝑦 ∣ ∃𝑥 ∈ 𝐴 𝑦 = 𝐵} ⊆ 𝐶) | ||
Theorem | eqri 28735 | Infer equality of classes from equivalence of membership. (Contributed by Thierry Arnoux, 7-Oct-2017.) |
⊢ Ⅎ𝑥𝐴 & ⊢ Ⅎ𝑥𝐵 & ⊢ (𝑥 ∈ 𝐴 ↔ 𝑥 ∈ 𝐵) ⇒ ⊢ 𝐴 = 𝐵 | ||
Theorem | rabss3d 28736* | Subclass law for restricted abstraction. (Contributed by Thierry Arnoux, 25-Sep-2017.) |
⊢ ((𝜑 ∧ (𝑥 ∈ 𝐴 ∧ 𝜓)) → 𝑥 ∈ 𝐵) ⇒ ⊢ (𝜑 → {𝑥 ∈ 𝐴 ∣ 𝜓} ⊆ {𝑥 ∈ 𝐵 ∣ 𝜓}) | ||
Theorem | inin 28737 | Intersection with an intersection. (Contributed by Thierry Arnoux, 27-Dec-2016.) |
⊢ (𝐴 ∩ (𝐴 ∩ 𝐵)) = (𝐴 ∩ 𝐵) | ||
Theorem | inindif 28738 | See inundif 3998. (Contributed by Thierry Arnoux, 13-Sep-2017.) |
⊢ ((𝐴 ∩ 𝐶) ∩ (𝐴 ∖ 𝐶)) = ∅ | ||
Theorem | difeq 28739 | Rewriting an equation with class difference, without using quantifiers. (Contributed by Thierry Arnoux, 24-Sep-2017.) |
⊢ ((𝐴 ∖ 𝐵) = 𝐶 ↔ ((𝐶 ∩ 𝐵) = ∅ ∧ (𝐶 ∪ 𝐵) = (𝐴 ∪ 𝐵))) | ||
Theorem | indifundif 28740 | A remarkable equation with sets. (Contributed by Thierry Arnoux, 18-May-2020.) |
⊢ (((𝐴 ∩ 𝐵) ∖ 𝐶) ∪ (𝐴 ∖ 𝐵)) = (𝐴 ∖ (𝐵 ∩ 𝐶)) | ||
Theorem | elpwincl1 28741 | Closure of intersection with regard to elementhood to a power set. (Contributed by Thierry Arnoux, 18-May-2020.) |
⊢ (𝜑 → 𝐴 ∈ 𝒫 𝐶) ⇒ ⊢ (𝜑 → (𝐴 ∩ 𝐵) ∈ 𝒫 𝐶) | ||
Theorem | elpwdifcl 28742 | Closure of class difference with regard to elementhood to a power set. (Contributed by Thierry Arnoux, 18-May-2020.) |
⊢ (𝜑 → 𝐴 ∈ 𝒫 𝐶) ⇒ ⊢ (𝜑 → (𝐴 ∖ 𝐵) ∈ 𝒫 𝐶) | ||
Theorem | elpwiuncl 28743* | Closure of indexed union with regard to elementhood to a power set. (Contributed by Thierry Arnoux, 27-May-2020.) |
⊢ (𝜑 → 𝐴 ∈ 𝑉) & ⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → 𝐵 ∈ 𝒫 𝐶) ⇒ ⊢ (𝜑 → ∪ 𝑘 ∈ 𝐴 𝐵 ∈ 𝒫 𝐶) | ||
Theorem | elpreq 28744 | Equality wihin a pair. (Contributed by Thierry Arnoux, 23-Aug-2017.) |
⊢ (𝜑 → 𝑋 ∈ {𝐴, 𝐵}) & ⊢ (𝜑 → 𝑌 ∈ {𝐴, 𝐵}) & ⊢ (𝜑 → (𝑋 = 𝐴 ↔ 𝑌 = 𝐴)) ⇒ ⊢ (𝜑 → 𝑋 = 𝑌) | ||
Theorem | ifeqeqx 28745* | An equality theorem tailored for ballotlemsf1o 29902. (Contributed by Thierry Arnoux, 14-Apr-2017.) |
⊢ (𝑥 = 𝑋 → 𝐴 = 𝐶) & ⊢ (𝑥 = 𝑌 → 𝐵 = 𝑎) & ⊢ (𝑥 = 𝑋 → (𝜒 ↔ 𝜃)) & ⊢ (𝑥 = 𝑌 → (𝜒 ↔ 𝜓)) & ⊢ (𝜑 → 𝑎 = 𝐶) & ⊢ ((𝜑 ∧ 𝜓) → 𝜃) & ⊢ (𝜑 → 𝑌 ∈ 𝑉) & ⊢ (𝜑 → 𝑋 ∈ 𝑊) ⇒ ⊢ ((𝜑 ∧ 𝑥 = if(𝜓, 𝑋, 𝑌)) → 𝑎 = if(𝜒, 𝐴, 𝐵)) | ||
Theorem | elimifd 28746 | Elimination of a conditional operator contained in a wff 𝜒. (Contributed by Thierry Arnoux, 25-Jan-2017.) |
⊢ (𝜑 → (if(𝜓, 𝐴, 𝐵) = 𝐴 → (𝜒 ↔ 𝜃))) & ⊢ (𝜑 → (if(𝜓, 𝐴, 𝐵) = 𝐵 → (𝜒 ↔ 𝜏))) ⇒ ⊢ (𝜑 → (𝜒 ↔ ((𝜓 ∧ 𝜃) ∨ (¬ 𝜓 ∧ 𝜏)))) | ||
Theorem | elim2if 28747 | Elimination of two conditional operators contained in a wff 𝜒. (Contributed by Thierry Arnoux, 25-Jan-2017.) |
⊢ (if(𝜑, 𝐴, if(𝜓, 𝐵, 𝐶)) = 𝐴 → (𝜒 ↔ 𝜃)) & ⊢ (if(𝜑, 𝐴, if(𝜓, 𝐵, 𝐶)) = 𝐵 → (𝜒 ↔ 𝜏)) & ⊢ (if(𝜑, 𝐴, if(𝜓, 𝐵, 𝐶)) = 𝐶 → (𝜒 ↔ 𝜂)) ⇒ ⊢ (𝜒 ↔ ((𝜑 ∧ 𝜃) ∨ (¬ 𝜑 ∧ ((𝜓 ∧ 𝜏) ∨ (¬ 𝜓 ∧ 𝜂))))) | ||
Theorem | elim2ifim 28748 | Elimination of two conditional operators for an implication. (Contributed by Thierry Arnoux, 25-Jan-2017.) |
⊢ (if(𝜑, 𝐴, if(𝜓, 𝐵, 𝐶)) = 𝐴 → (𝜒 ↔ 𝜃)) & ⊢ (if(𝜑, 𝐴, if(𝜓, 𝐵, 𝐶)) = 𝐵 → (𝜒 ↔ 𝜏)) & ⊢ (if(𝜑, 𝐴, if(𝜓, 𝐵, 𝐶)) = 𝐶 → (𝜒 ↔ 𝜂)) & ⊢ (𝜑 → 𝜃) & ⊢ ((¬ 𝜑 ∧ 𝜓) → 𝜏) & ⊢ ((¬ 𝜑 ∧ ¬ 𝜓) → 𝜂) ⇒ ⊢ 𝜒 | ||
Theorem | uniinn0 28749* | Sufficient and necessary condition for a union to intersect with a given set. (Contributed by Thierry Arnoux, 27-Jan-2020.) |
⊢ ((∪ 𝐴 ∩ 𝐵) ≠ ∅ ↔ ∃𝑥 ∈ 𝐴 (𝑥 ∩ 𝐵) ≠ ∅) | ||
Theorem | uniin1 28750* | Union of intersection. Generalization of half of theorem "Distributive laws" in [Enderton] p. 30. (Contributed by Thierry Arnoux, 21-Jun-2020.) |
⊢ ∪ 𝑥 ∈ 𝐴 (𝑥 ∩ 𝐵) = (∪ 𝐴 ∩ 𝐵) | ||
Theorem | uniin2 28751* | Union of intersection. Generalization of half of theorem "Distributive laws" in [Enderton] p. 30. (Contributed by Thierry Arnoux, 21-Jun-2020.) |
⊢ ∪ 𝑥 ∈ 𝐵 (𝐴 ∩ 𝑥) = (𝐴 ∩ ∪ 𝐵) | ||
Theorem | difuncomp 28752 | Express a class difference using unions and class complements. (Contributed by Thierry Arnoux, 21-Jun-2020.) |
⊢ (𝐴 ⊆ 𝐶 → (𝐴 ∖ 𝐵) = (𝐶 ∖ ((𝐶 ∖ 𝐴) ∪ 𝐵))) | ||
Theorem | pwuniss 28753 | Condition for a class union to be a subset. (Contributed by Thierry Arnoux, 21-Jun-2020.) |
⊢ (𝐴 ⊆ 𝒫 𝐵 → ∪ 𝐴 ⊆ 𝐵) | ||
Theorem | elpwunicl 28754 | Closure of a set union with regard to elementhood to a power set. (Contributed by Thierry Arnoux, 21-Jun-2020.) |
⊢ (𝜑 → 𝐵 ∈ 𝑉) & ⊢ (𝜑 → 𝐴 ∈ 𝒫 𝒫 𝐵) ⇒ ⊢ (𝜑 → ∪ 𝐴 ∈ 𝒫 𝐵) | ||
Theorem | cbviunf 28755* | Rule used to change the bound variables in an indexed union, with the substitution specified implicitly by the hypothesis. (Contributed by NM, 26-Mar-2006.) (Revised by Andrew Salmon, 25-Jul-2011.) |
⊢ Ⅎ𝑥𝐴 & ⊢ Ⅎ𝑦𝐴 & ⊢ Ⅎ𝑦𝐵 & ⊢ Ⅎ𝑥𝐶 & ⊢ (𝑥 = 𝑦 → 𝐵 = 𝐶) ⇒ ⊢ ∪ 𝑥 ∈ 𝐴 𝐵 = ∪ 𝑦 ∈ 𝐴 𝐶 | ||
Theorem | iuneq12daf 28756 | Equality deduction for indexed union, deduction version. (Contributed by Thierry Arnoux, 13-Mar-2017.) |
⊢ Ⅎ𝑥𝜑 & ⊢ Ⅎ𝑥𝐴 & ⊢ Ⅎ𝑥𝐵 & ⊢ (𝜑 → 𝐴 = 𝐵) & ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → 𝐶 = 𝐷) ⇒ ⊢ (𝜑 → ∪ 𝑥 ∈ 𝐴 𝐶 = ∪ 𝑥 ∈ 𝐵 𝐷) | ||
Theorem | iunin1f 28757 | Indexed union of intersection. Generalization of half of theorem "Distributive laws" in [Enderton] p. 30. Use uniiun 4509 to recover Enderton's theorem. (Contributed by NM, 26-Mar-2004.) (Revised by Thierry Arnoux, 2-May-2020.) |
⊢ Ⅎ𝑥𝐶 ⇒ ⊢ ∪ 𝑥 ∈ 𝐴 (𝐵 ∩ 𝐶) = (∪ 𝑥 ∈ 𝐴 𝐵 ∩ 𝐶) | ||
Theorem | iunxsngf 28758* | A singleton index picks out an instance of an indexed union's argument. (Contributed by Mario Carneiro, 25-Jun-2016.) (Revised by Thierry Arnoux, 2-May-2020.) |
⊢ Ⅎ𝑥𝐶 & ⊢ (𝑥 = 𝐴 → 𝐵 = 𝐶) ⇒ ⊢ (𝐴 ∈ 𝑉 → ∪ 𝑥 ∈ {𝐴}𝐵 = 𝐶) | ||
Theorem | ssiun3 28759* | Subset equivalence for an indexed union. (Contributed by Thierry Arnoux, 17-Oct-2016.) |
⊢ (∀𝑦 ∈ 𝐶 ∃𝑥 ∈ 𝐴 𝑦 ∈ 𝐵 ↔ 𝐶 ⊆ ∪ 𝑥 ∈ 𝐴 𝐵) | ||
Theorem | ssiun2sf 28760 | Subset relationship for an indexed union. (Contributed by Thierry Arnoux, 31-Dec-2016.) |
⊢ Ⅎ𝑥𝐴 & ⊢ Ⅎ𝑥𝐶 & ⊢ Ⅎ𝑥𝐷 & ⊢ (𝑥 = 𝐶 → 𝐵 = 𝐷) ⇒ ⊢ (𝐶 ∈ 𝐴 → 𝐷 ⊆ ∪ 𝑥 ∈ 𝐴 𝐵) | ||
Theorem | iuninc 28761* | The union of an increasing collection of sets is its last element. (Contributed by Thierry Arnoux, 22-Jan-2017.) |
⊢ (𝜑 → 𝐹 Fn ℕ) & ⊢ ((𝜑 ∧ 𝑛 ∈ ℕ) → (𝐹‘𝑛) ⊆ (𝐹‘(𝑛 + 1))) ⇒ ⊢ ((𝜑 ∧ 𝑖 ∈ ℕ) → ∪ 𝑛 ∈ (1...𝑖)(𝐹‘𝑛) = (𝐹‘𝑖)) | ||
Theorem | iundifdifd 28762* | The intersection of a set is the complement of the union of the complements. (Contributed by Thierry Arnoux, 19-Dec-2016.) |
⊢ (𝐴 ⊆ 𝒫 𝑂 → (𝐴 ≠ ∅ → ∩ 𝐴 = (𝑂 ∖ ∪ 𝑥 ∈ 𝐴 (𝑂 ∖ 𝑥)))) | ||
Theorem | iundifdif 28763* | The intersection of a set is the complement of the union of the complements. TODO: shorten using iundifdifd 28762. (Contributed by Thierry Arnoux, 4-Sep-2016.) |
⊢ 𝑂 ∈ V & ⊢ 𝐴 ⊆ 𝒫 𝑂 ⇒ ⊢ (𝐴 ≠ ∅ → ∩ 𝐴 = (𝑂 ∖ ∪ 𝑥 ∈ 𝐴 (𝑂 ∖ 𝑥))) | ||
Theorem | iunrdx 28764* | Re-index an indexed union. (Contributed by Thierry Arnoux, 6-Apr-2017.) |
⊢ (𝜑 → 𝐹:𝐴–onto→𝐶) & ⊢ ((𝜑 ∧ 𝑦 = (𝐹‘𝑥)) → 𝐷 = 𝐵) ⇒ ⊢ (𝜑 → ∪ 𝑥 ∈ 𝐴 𝐵 = ∪ 𝑦 ∈ 𝐶 𝐷) | ||
Theorem | iunpreima 28765* | Preimage of an indexed union. (Contributed by Thierry Arnoux, 27-Mar-2018.) |
⊢ (Fun 𝐹 → (◡𝐹 “ ∪ 𝑥 ∈ 𝐴 𝐵) = ∪ 𝑥 ∈ 𝐴 (◡𝐹 “ 𝐵)) | ||
Theorem | disjnf 28766* | In case 𝑥 is not free in 𝐵, disjointness is not so interesting since it reduces to cases where 𝐴 is a singleton. (Google Groups discussion with Peter Masza.) (Contributed by Thierry Arnoux, 26-Jul-2018.) |
⊢ (Disj 𝑥 ∈ 𝐴 𝐵 ↔ (𝐵 = ∅ ∨ ∃*𝑥 𝑥 ∈ 𝐴)) | ||
Theorem | cbvdisjf 28767* | Change bound variables in a disjoint collection. (Contributed by Thierry Arnoux, 6-Apr-2017.) |
⊢ Ⅎ𝑥𝐴 & ⊢ Ⅎ𝑦𝐵 & ⊢ Ⅎ𝑥𝐶 & ⊢ (𝑥 = 𝑦 → 𝐵 = 𝐶) ⇒ ⊢ (Disj 𝑥 ∈ 𝐴 𝐵 ↔ Disj 𝑦 ∈ 𝐴 𝐶) | ||
Theorem | disjss1f 28768 | A subset of a disjoint collection is disjoint. (Contributed by Thierry Arnoux, 6-Apr-2017.) |
⊢ Ⅎ𝑥𝐴 & ⊢ Ⅎ𝑥𝐵 ⇒ ⊢ (𝐴 ⊆ 𝐵 → (Disj 𝑥 ∈ 𝐵 𝐶 → Disj 𝑥 ∈ 𝐴 𝐶)) | ||
Theorem | disjeq1f 28769 | Equality theorem for disjoint collection. (Contributed by Mario Carneiro, 14-Nov-2016.) |
⊢ Ⅎ𝑥𝐴 & ⊢ Ⅎ𝑥𝐵 ⇒ ⊢ (𝐴 = 𝐵 → (Disj 𝑥 ∈ 𝐴 𝐶 ↔ Disj 𝑥 ∈ 𝐵 𝐶)) | ||
Theorem | disjdifprg 28770* | A trivial partition into a subset and its complement. (Contributed by Thierry Arnoux, 25-Dec-2016.) |
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → Disj 𝑥 ∈ {(𝐵 ∖ 𝐴), 𝐴}𝑥) | ||
Theorem | disjdifprg2 28771* | A trivial partition of a set into its difference and intersection with another set. (Contributed by Thierry Arnoux, 25-Dec-2016.) |
⊢ (𝐴 ∈ 𝑉 → Disj 𝑥 ∈ {(𝐴 ∖ 𝐵), (𝐴 ∩ 𝐵)}𝑥) | ||
Theorem | disji2f 28772* | Property of a disjoint collection: if 𝐵(𝑥) = 𝐶 and 𝐵(𝑌) = 𝐷, and 𝑥 ≠ 𝑌, then 𝐵 and 𝐶 are disjoint. (Contributed by Thierry Arnoux, 30-Dec-2016.) |
⊢ Ⅎ𝑥𝐶 & ⊢ (𝑥 = 𝑌 → 𝐵 = 𝐶) ⇒ ⊢ ((Disj 𝑥 ∈ 𝐴 𝐵 ∧ (𝑥 ∈ 𝐴 ∧ 𝑌 ∈ 𝐴) ∧ 𝑥 ≠ 𝑌) → (𝐵 ∩ 𝐶) = ∅) | ||
Theorem | disjif 28773* | Property of a disjoint collection: if 𝐵(𝑥) and 𝐵(𝑌) = 𝐷 have a common element 𝑍, then 𝑥 = 𝑌. (Contributed by Thierry Arnoux, 30-Dec-2016.) |
⊢ Ⅎ𝑥𝐶 & ⊢ (𝑥 = 𝑌 → 𝐵 = 𝐶) ⇒ ⊢ ((Disj 𝑥 ∈ 𝐴 𝐵 ∧ (𝑥 ∈ 𝐴 ∧ 𝑌 ∈ 𝐴) ∧ (𝑍 ∈ 𝐵 ∧ 𝑍 ∈ 𝐶)) → 𝑥 = 𝑌) | ||
Theorem | disjorf 28774* | Two ways to say that a collection 𝐵(𝑖) for 𝑖 ∈ 𝐴 is disjoint. (Contributed by Thierry Arnoux, 8-Mar-2017.) |
⊢ Ⅎ𝑖𝐴 & ⊢ Ⅎ𝑗𝐴 & ⊢ (𝑖 = 𝑗 → 𝐵 = 𝐶) ⇒ ⊢ (Disj 𝑖 ∈ 𝐴 𝐵 ↔ ∀𝑖 ∈ 𝐴 ∀𝑗 ∈ 𝐴 (𝑖 = 𝑗 ∨ (𝐵 ∩ 𝐶) = ∅)) | ||
Theorem | disjorsf 28775* | Two ways to say that a collection 𝐵(𝑖) for 𝑖 ∈ 𝐴 is disjoint. (Contributed by Thierry Arnoux, 8-Mar-2017.) |
⊢ Ⅎ𝑥𝐴 ⇒ ⊢ (Disj 𝑥 ∈ 𝐴 𝐵 ↔ ∀𝑖 ∈ 𝐴 ∀𝑗 ∈ 𝐴 (𝑖 = 𝑗 ∨ (⦋𝑖 / 𝑥⦌𝐵 ∩ ⦋𝑗 / 𝑥⦌𝐵) = ∅)) | ||
Theorem | disjif2 28776* | Property of a disjoint collection: if 𝐵(𝑥) and 𝐵(𝑌) = 𝐷 have a common element 𝑍, then 𝑥 = 𝑌. (Contributed by Thierry Arnoux, 6-Apr-2017.) |
⊢ Ⅎ𝑥𝐴 & ⊢ Ⅎ𝑥𝐶 & ⊢ (𝑥 = 𝑌 → 𝐵 = 𝐶) ⇒ ⊢ ((Disj 𝑥 ∈ 𝐴 𝐵 ∧ (𝑥 ∈ 𝐴 ∧ 𝑌 ∈ 𝐴) ∧ (𝑍 ∈ 𝐵 ∧ 𝑍 ∈ 𝐶)) → 𝑥 = 𝑌) | ||
Theorem | disjabrex 28777* | Rewriting a disjoint collection into a partition of its image set. (Contributed by Thierry Arnoux, 30-Dec-2016.) |
⊢ (Disj 𝑥 ∈ 𝐴 𝐵 → Disj 𝑦 ∈ {𝑧 ∣ ∃𝑥 ∈ 𝐴 𝑧 = 𝐵}𝑦) | ||
Theorem | disjabrexf 28778* | Rewriting a disjoint collection into a partition of its image set. (Contributed by Thierry Arnoux, 30-Dec-2016.) (Revised by Thierry Arnoux, 9-Mar-2017.) |
⊢ Ⅎ𝑥𝐴 ⇒ ⊢ (Disj 𝑥 ∈ 𝐴 𝐵 → Disj 𝑦 ∈ {𝑧 ∣ ∃𝑥 ∈ 𝐴 𝑧 = 𝐵}𝑦) | ||
Theorem | disjpreima 28779* | A preimage of a disjoint set is disjoint. (Contributed by Thierry Arnoux, 7-Feb-2017.) |
⊢ ((Fun 𝐹 ∧ Disj 𝑥 ∈ 𝐴 𝐵) → Disj 𝑥 ∈ 𝐴 (◡𝐹 “ 𝐵)) | ||
Theorem | disjrnmpt 28780* | Rewriting a disjoint collection using the range of a mapping. (Contributed by Thierry Arnoux, 27-May-2020.) |
⊢ (Disj 𝑥 ∈ 𝐴 𝐵 → Disj 𝑦 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵)𝑦) | ||
Theorem | disjin 28781 | If a collection is disjoint, so is the collection of the intersections with a given set. (Contributed by Thierry Arnoux, 14-Feb-2017.) |
⊢ (Disj 𝑥 ∈ 𝐵 𝐶 → Disj 𝑥 ∈ 𝐵 (𝐶 ∩ 𝐴)) | ||
Theorem | disjin2 28782 | If a collection is disjoint, so is the collection of the intersections with a given set. (Contributed by Thierry Arnoux, 21-Jun-2020.) |
⊢ (Disj 𝑥 ∈ 𝐵 𝐶 → Disj 𝑥 ∈ 𝐵 (𝐴 ∩ 𝐶)) | ||
Theorem | disjxpin 28783* | Derive a disjunction over a Cartesian product from the disjunctions over its first and second elements. (Contributed by Thierry Arnoux, 9-Mar-2018.) |
⊢ (𝑥 = (1st ‘𝑝) → 𝐶 = 𝐸) & ⊢ (𝑦 = (2nd ‘𝑝) → 𝐷 = 𝐹) & ⊢ (𝜑 → Disj 𝑥 ∈ 𝐴 𝐶) & ⊢ (𝜑 → Disj 𝑦 ∈ 𝐵 𝐷) ⇒ ⊢ (𝜑 → Disj 𝑝 ∈ (𝐴 × 𝐵)(𝐸 ∩ 𝐹)) | ||
Theorem | iundisjf 28784* | Rewrite a countable union as a disjoint union. Cf. iundisj 23123. (Contributed by Thierry Arnoux, 31-Dec-2016.) |
⊢ Ⅎ𝑘𝐴 & ⊢ Ⅎ𝑛𝐵 & ⊢ (𝑛 = 𝑘 → 𝐴 = 𝐵) ⇒ ⊢ ∪ 𝑛 ∈ ℕ 𝐴 = ∪ 𝑛 ∈ ℕ (𝐴 ∖ ∪ 𝑘 ∈ (1..^𝑛)𝐵) | ||
Theorem | iundisj2f 28785* | A disjoint union is disjoint. Cf. iundisj2 23124. (Contributed by Thierry Arnoux, 30-Dec-2016.) |
⊢ Ⅎ𝑘𝐴 & ⊢ Ⅎ𝑛𝐵 & ⊢ (𝑛 = 𝑘 → 𝐴 = 𝐵) ⇒ ⊢ Disj 𝑛 ∈ ℕ (𝐴 ∖ ∪ 𝑘 ∈ (1..^𝑛)𝐵) | ||
Theorem | disjrdx 28786* | Re-index a disjunct collection statement. (Contributed by Thierry Arnoux, 7-Apr-2017.) |
⊢ (𝜑 → 𝐹:𝐴–1-1-onto→𝐶) & ⊢ ((𝜑 ∧ 𝑦 = (𝐹‘𝑥)) → 𝐷 = 𝐵) ⇒ ⊢ (𝜑 → (Disj 𝑥 ∈ 𝐴 𝐵 ↔ Disj 𝑦 ∈ 𝐶 𝐷)) | ||
Theorem | disjex 28787* | Two ways to say that two classes are disjoint (or equal). (Contributed by Thierry Arnoux, 4-Oct-2016.) |
⊢ ((∃𝑧(𝑧 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵) → 𝐴 = 𝐵) ↔ (𝐴 = 𝐵 ∨ (𝐴 ∩ 𝐵) = ∅)) | ||
Theorem | disjexc 28788* | A variant of disjex 28787, applicable for more generic families. (Contributed by Thierry Arnoux, 4-Oct-2016.) |
⊢ (𝑥 = 𝑦 → 𝐴 = 𝐵) ⇒ ⊢ ((∃𝑧(𝑧 ∈ 𝐴 ∧ 𝑧 ∈ 𝐵) → 𝑥 = 𝑦) → (𝐴 = 𝐵 ∨ (𝐴 ∩ 𝐵) = ∅)) | ||
Theorem | disjunsn 28789* | Append an element to a disjoint collection. Similar to ralunsn 4360, gsumunsn 18182, etc. (Contributed by Thierry Arnoux, 28-Mar-2018.) |
⊢ (𝑥 = 𝑀 → 𝐵 = 𝐶) ⇒ ⊢ ((𝑀 ∈ 𝑉 ∧ ¬ 𝑀 ∈ 𝐴) → (Disj 𝑥 ∈ (𝐴 ∪ {𝑀})𝐵 ↔ (Disj 𝑥 ∈ 𝐴 𝐵 ∧ (∪ 𝑥 ∈ 𝐴 𝐵 ∩ 𝐶) = ∅))) | ||
Theorem | disjun0 28790* | Adding the empty element preserves disjointness. (Contributed by Thierry Arnoux, 30-May-2020.) |
⊢ (Disj 𝑥 ∈ 𝐴 𝑥 → Disj 𝑥 ∈ (𝐴 ∪ {∅})𝑥) | ||
Theorem | disjiunel 28791* | A set of elements B of a disjoint set A is disjoint with another element of that set. (Contributed by Thierry Arnoux, 24-May-2020.) |
⊢ (𝜑 → Disj 𝑥 ∈ 𝐴 𝐵) & ⊢ (𝑥 = 𝑌 → 𝐵 = 𝐷) & ⊢ (𝜑 → 𝐸 ⊆ 𝐴) & ⊢ (𝜑 → 𝑌 ∈ (𝐴 ∖ 𝐸)) ⇒ ⊢ (𝜑 → (∪ 𝑥 ∈ 𝐸 𝐵 ∩ 𝐷) = ∅) | ||
Theorem | disjuniel 28792* | A set of elements B of a disjoint set A is disjoint with another element of that set. (Contributed by Thierry Arnoux, 24-May-2020.) |
⊢ (𝜑 → Disj 𝑥 ∈ 𝐴 𝑥) & ⊢ (𝜑 → 𝐵 ⊆ 𝐴) & ⊢ (𝜑 → 𝐶 ∈ (𝐴 ∖ 𝐵)) ⇒ ⊢ (𝜑 → (∪ 𝐵 ∩ 𝐶) = ∅) | ||
Theorem | xpdisjres 28793 | Restriction of a constant function (or other Cartesian product) outside of its domain. (Contributed by Thierry Arnoux, 25-Jan-2017.) |
⊢ ((𝐴 ∩ 𝐶) = ∅ → ((𝐴 × 𝐵) ↾ 𝐶) = ∅) | ||
Theorem | opeldifid 28794 | Ordered pair elementhood outside of the diagonal. (Contributed by Thierry Arnoux, 1-Jan-2020.) |
⊢ (Rel 𝐴 → (〈𝑋, 𝑌〉 ∈ (𝐴 ∖ I ) ↔ (〈𝑋, 𝑌〉 ∈ 𝐴 ∧ 𝑋 ≠ 𝑌))) | ||
Theorem | difres 28795 | Case when class difference in unaffected by restriction. (Contributed by Thierry Arnoux, 1-Jan-2020.) |
⊢ (𝐴 ⊆ (𝐵 × V) → (𝐴 ∖ (𝐶 ↾ 𝐵)) = (𝐴 ∖ 𝐶)) | ||
Theorem | imadifxp 28796 | Image of the difference with a Cartesian product. (Contributed by Thierry Arnoux, 13-Dec-2017.) |
⊢ (𝐶 ⊆ 𝐴 → ((𝑅 ∖ (𝐴 × 𝐵)) “ 𝐶) = ((𝑅 “ 𝐶) ∖ 𝐵)) | ||
Theorem | relfi 28797 | A relation (set) is finite if and only if both its domain and range are finite. (Contributed by Thierry Arnoux, 27-Aug-2017.) |
⊢ (Rel 𝐴 → (𝐴 ∈ Fin ↔ (dom 𝐴 ∈ Fin ∧ ran 𝐴 ∈ Fin))) | ||
Theorem | fcoinver 28798 | Build an equivalence relation from a function. Two values are equivalent if they have the same image by the function. See also fcoinvbr 28799. (Contributed by Thierry Arnoux, 3-Jan-2020.) |
⊢ (𝐹 Fn 𝑋 → (◡𝐹 ∘ 𝐹) Er 𝑋) | ||
Theorem | fcoinvbr 28799 | Binary relation for the equivalence relation from fcoinver 28798. (Contributed by Thierry Arnoux, 3-Jan-2020.) |
⊢ ∼ = (◡𝐹 ∘ 𝐹) ⇒ ⊢ ((𝐹 Fn 𝐴 ∧ 𝑋 ∈ 𝐴 ∧ 𝑌 ∈ 𝐴) → (𝑋 ∼ 𝑌 ↔ (𝐹‘𝑋) = (𝐹‘𝑌))) | ||
Theorem | brabgaf 28800* | The law of concretion for a binary relation. (Contributed by Mario Carneiro, 19-Dec-2013.) (Revised by Thierry Arnoux, 17-May-2020.) |
⊢ Ⅎ𝑥𝜓 & ⊢ ((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) → (𝜑 ↔ 𝜓)) & ⊢ 𝑅 = {〈𝑥, 𝑦〉 ∣ 𝜑} ⇒ ⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → (𝐴𝑅𝐵 ↔ 𝜓)) |
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