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Type | Label | Description |
---|---|---|
Statement | ||
Theorem | symrefref2 35801 | Symmetry is a sufficient condition for the equivalence of two versions of the reflexive relation, see also symrefref3 35802. (Contributed by Peter Mazsa, 19-Jul-2018.) |
⊢ (◡𝑅 ⊆ 𝑅 → (( I ∩ (dom 𝑅 × ran 𝑅)) ⊆ 𝑅 ↔ ( I ↾ dom 𝑅) ⊆ 𝑅)) | ||
Theorem | symrefref3 35802* | Symmetry is a sufficient condition for the equivalence of two versions of the reflexive relation, see also symrefref2 35801. (Contributed by Peter Mazsa, 23-Aug-2021.) (Proof modification is discouraged.) |
⊢ (∀𝑥∀𝑦(𝑥𝑅𝑦 → 𝑦𝑅𝑥) → (∀𝑥 ∈ dom 𝑅∀𝑦 ∈ ran 𝑅(𝑥 = 𝑦 → 𝑥𝑅𝑦) ↔ ∀𝑥 ∈ dom 𝑅 𝑥𝑅𝑥)) | ||
Theorem | refsymrels2 35803 | Elements of the class of reflexive relations which are elements of the class of symmetric relations as well (like the elements of the class of equivalence relations dfeqvrels2 35825) can use the restricted version for their reflexive part (see below), not just the ( I ∩ (dom 𝑟 × ran 𝑟)) ⊆ 𝑟 version of dfrefrels2 35755, cf. the comment of dfrefrels2 35755. (Contributed by Peter Mazsa, 20-Jul-2019.) |
⊢ ( RefRels ∩ SymRels ) = {𝑟 ∈ Rels ∣ (( I ↾ dom 𝑟) ⊆ 𝑟 ∧ ◡𝑟 ⊆ 𝑟)} | ||
Theorem | refsymrels3 35804* | Elements of the class of reflexive relations which are elements of the class of symmetric relations as well (like the elements of the class of equivalence relations dfeqvrels3 35826) can use the ∀𝑥 ∈ dom 𝑟𝑥𝑟𝑥 version for their reflexive part, not just the ∀𝑥 ∈ dom 𝑟∀𝑦 ∈ ran 𝑟(𝑥 = 𝑦 → 𝑥𝑟𝑦) version of dfrefrels3 35756, cf. the comment of dfrefrel3 35758. (Contributed by Peter Mazsa, 22-Jul-2019.) (Proof modification is discouraged.) |
⊢ ( RefRels ∩ SymRels ) = {𝑟 ∈ Rels ∣ (∀𝑥 ∈ dom 𝑟 𝑥𝑟𝑥 ∧ ∀𝑥∀𝑦(𝑥𝑟𝑦 → 𝑦𝑟𝑥))} | ||
Theorem | refsymrel2 35805 | A relation which is reflexive and symmetric (like an equivalence relation) can use the restricted version for their reflexive part (see below), not just the ( I ∩ (dom 𝑅 × ran 𝑅)) ⊆ 𝑅 version of dfrefrel2 35757, cf. the comment of dfrefrels2 35755. (Contributed by Peter Mazsa, 23-Aug-2021.) |
⊢ (( RefRel 𝑅 ∧ SymRel 𝑅) ↔ ((( I ↾ dom 𝑅) ⊆ 𝑅 ∧ ◡𝑅 ⊆ 𝑅) ∧ Rel 𝑅)) | ||
Theorem | refsymrel3 35806* | A relation which is reflexive and symmetric (like an equivalence relation) can use the ∀𝑥 ∈ dom 𝑅𝑥𝑅𝑥 version for its reflexive part, not just the ∀𝑥 ∈ dom 𝑅∀𝑦 ∈ ran 𝑅(𝑥 = 𝑦 → 𝑥𝑅𝑦) version of dfrefrel3 35758, cf. the comment of dfrefrel3 35758. (Contributed by Peter Mazsa, 23-Aug-2021.) |
⊢ (( RefRel 𝑅 ∧ SymRel 𝑅) ↔ ((∀𝑥 ∈ dom 𝑅 𝑥𝑅𝑥 ∧ ∀𝑥∀𝑦(𝑥𝑅𝑦 → 𝑦𝑅𝑥)) ∧ Rel 𝑅)) | ||
Theorem | elrefsymrels2 35807 | Elements of the class of reflexive relations which are elements of the class of symmetric relations as well (like the elements of the class of equivalence relations dfeqvrels2 35825) can use the restricted version for their reflexive part (see below), not just the ( I ∩ (dom 𝑅 × ran 𝑅)) ⊆ 𝑅 version of dfrefrels2 35755, cf. the comment of dfrefrels2 35755. (Contributed by Peter Mazsa, 22-Jul-2019.) |
⊢ (𝑅 ∈ ( RefRels ∩ SymRels ) ↔ ((( I ↾ dom 𝑅) ⊆ 𝑅 ∧ ◡𝑅 ⊆ 𝑅) ∧ 𝑅 ∈ Rels )) | ||
Theorem | elrefsymrels3 35808* | Elements of the class of reflexive relations which are elements of the class of symmetric relations as well (like the elements of the class of equivalence relations dfeqvrels3 35826) can use the ∀𝑥 ∈ dom 𝑅𝑥𝑅𝑥 version for their reflexive part, not just the ∀𝑥 ∈ dom 𝑅∀𝑦 ∈ ran 𝑅(𝑥 = 𝑦 → 𝑥𝑅𝑦) version of dfrefrels3 35756, cf. the comment of dfrefrel3 35758. (Contributed by Peter Mazsa, 22-Jul-2019.) (Proof modification is discouraged.) |
⊢ (𝑅 ∈ ( RefRels ∩ SymRels ) ↔ ((∀𝑥 ∈ dom 𝑅 𝑥𝑅𝑥 ∧ ∀𝑥∀𝑦(𝑥𝑅𝑦 → 𝑦𝑅𝑥)) ∧ 𝑅 ∈ Rels )) | ||
Theorem | elrefsymrelsrel 35809 | For sets, being an element of the class of reflexive and symmetric relations is equivalent to satisfying the reflexive and symmetric relation predicates. (Contributed by Peter Mazsa, 23-Aug-2021.) |
⊢ (𝑅 ∈ 𝑉 → (𝑅 ∈ ( RefRels ∩ SymRels ) ↔ ( RefRel 𝑅 ∧ SymRel 𝑅))) | ||
Definition | df-trs 35810 |
Define the class of all transitive sets (versus the transitive class
defined in df-tr 5175). It is used only by df-trrels 35811.
Note the similarity of the definitions of df-refs 35752, df-syms 35780 and df-trs 35810. (Contributed by Peter Mazsa, 17-Jul-2021.) |
⊢ Trs = {𝑥 ∣ ((𝑥 ∩ (dom 𝑥 × ran 𝑥)) ∘ (𝑥 ∩ (dom 𝑥 × ran 𝑥))) S (𝑥 ∩ (dom 𝑥 × ran 𝑥))} | ||
Definition | df-trrels 35811 |
Define the class of transitive relations. For sets, being an element of
the class of transitive relations is equivalent to satisfying the
transitive relation predicate, see eltrrelsrel 35819. Alternate definitions
are dftrrels2 35813 and dftrrels3 35814.
This definition is similar to the definitions of the classes of reflexive (df-refrels 35753) and symmetric (df-symrels 35781) relations. (Contributed by Peter Mazsa, 7-Jul-2019.) |
⊢ TrRels = ( Trs ∩ Rels ) | ||
Definition | df-trrel 35812 | Define the transitive relation predicate. (Read: 𝑅 is a transitive relation.) For sets, being an element of the class of transitive relations (df-trrels 35811) is equivalent to satisfying the transitive relation predicate, see eltrrelsrel 35819. Alternate definitions are dftrrel2 35815 and dftrrel3 35816. (Contributed by Peter Mazsa, 17-Jul-2021.) |
⊢ ( TrRel 𝑅 ↔ (((𝑅 ∩ (dom 𝑅 × ran 𝑅)) ∘ (𝑅 ∩ (dom 𝑅 × ran 𝑅))) ⊆ (𝑅 ∩ (dom 𝑅 × ran 𝑅)) ∧ Rel 𝑅)) | ||
Theorem | dftrrels2 35813 |
Alternate definition of the class of transitive relations.
I'd prefer to define the class of transitive relations by using the definition of composition by [Suppes] p. 63. df-coSUP (𝐴 ∘ 𝐵) = {〈𝑥, 𝑦〉 ∣ ∃𝑢(𝑥𝐴𝑢 ∧ 𝑢𝐵𝑦)} as opposed to the present definition of composition df-co 5566 (𝐴 ∘ 𝐵) = {〈𝑥, 𝑦〉 ∣ ∃𝑢(𝑥𝐵𝑢 ∧ 𝑢𝐴𝑦)} because the Suppes definition keeps the order of 𝐴, 𝐵, 𝐶, 𝑅, 𝑆, 𝑇 by default in trsinxpSUP (((𝑅 ∩ (𝐴 × 𝐵)) ∘ (𝑆 ∩ (𝐵 × 𝐶))) ⊆ (𝑇 ∩ (𝐴 × 𝐶)) ↔ ∀𝑥 ∈ 𝐴∀𝑦 ∈ 𝐵∀ 𝑧 ∈ 𝐶((𝑥𝑅𝑦 ∧ 𝑦𝑆𝑧) → 𝑥𝑇𝑧)) while the present definition of composition disarranges them: trsinxp (((𝑆 ∩ (𝐵 × 𝐶)) ∘ (𝑅 ∩ (𝐴 × 𝐵))) ⊆ (𝑇 ∩ (𝐴 × 𝐶 )) ↔ ∀𝑥 ∈ 𝐴∀𝑦 ∈ 𝐵∀𝑧 ∈ 𝐶((𝑥𝑅𝑦 ∧ 𝑦𝑆𝑧) → 𝑥𝑇𝑧) ). This is not mission critical to me, the implication of the Suppes definition is just more aesthetic, at least in the above case. If we swap to the Suppes definition of class composition, I would define the present class of all transitive sets as df-trsSUP and I would consider to switch the definition of the class of cosets by 𝑅 from the present df-coss 35661 to a df-cossSUP. But perhaps there is a mathematical reason to keep the present definition of composition. (Contributed by Peter Mazsa, 21-Jul-2021.) |
⊢ TrRels = {𝑟 ∈ Rels ∣ (𝑟 ∘ 𝑟) ⊆ 𝑟} | ||
Theorem | dftrrels3 35814* | Alternate definition of the class of transitive relations. (Contributed by Peter Mazsa, 22-Jul-2021.) |
⊢ TrRels = {𝑟 ∈ Rels ∣ ∀𝑥∀𝑦∀𝑧((𝑥𝑟𝑦 ∧ 𝑦𝑟𝑧) → 𝑥𝑟𝑧)} | ||
Theorem | dftrrel2 35815 | Alternate definition of the transitive relation predicate. (Contributed by Peter Mazsa, 22-Aug-2021.) |
⊢ ( TrRel 𝑅 ↔ ((𝑅 ∘ 𝑅) ⊆ 𝑅 ∧ Rel 𝑅)) | ||
Theorem | dftrrel3 35816* | Alternate definition of the transitive relation predicate. (Contributed by Peter Mazsa, 22-Aug-2021.) |
⊢ ( TrRel 𝑅 ↔ (∀𝑥∀𝑦∀𝑧((𝑥𝑅𝑦 ∧ 𝑦𝑅𝑧) → 𝑥𝑅𝑧) ∧ Rel 𝑅)) | ||
Theorem | eltrrels2 35817 | Element of the class of transitive relations. (Contributed by Peter Mazsa, 22-Aug-2021.) |
⊢ (𝑅 ∈ TrRels ↔ ((𝑅 ∘ 𝑅) ⊆ 𝑅 ∧ 𝑅 ∈ Rels )) | ||
Theorem | eltrrels3 35818* | Element of the class of transitive relations. (Contributed by Peter Mazsa, 22-Aug-2021.) |
⊢ (𝑅 ∈ TrRels ↔ (∀𝑥∀𝑦∀𝑧((𝑥𝑅𝑦 ∧ 𝑦𝑅𝑧) → 𝑥𝑅𝑧) ∧ 𝑅 ∈ Rels )) | ||
Theorem | eltrrelsrel 35819 | For sets, being an element of the class of transitive relations is equivalent to satisfying the transitive relation predicate. (Contributed by Peter Mazsa, 22-Aug-2021.) |
⊢ (𝑅 ∈ 𝑉 → (𝑅 ∈ TrRels ↔ TrRel 𝑅)) | ||
Theorem | trreleq 35820 | Equality theorem for the transitive relation predicate. (Contributed by Peter Mazsa, 15-Apr-2019.) (Revised by Peter Mazsa, 23-Sep-2021.) |
⊢ (𝑅 = 𝑆 → ( TrRel 𝑅 ↔ TrRel 𝑆)) | ||
Definition | df-eqvrels 35821 | Define the class of equivalence relations. For sets, being an element of the class of equivalence relations is equivalent to satisfying the equivalence relation predicate, see eleqvrelsrel 35831. Alternate definitions are dfeqvrels2 35825 and dfeqvrels3 35826. (Contributed by Peter Mazsa, 7-Nov-2018.) |
⊢ EqvRels = (( RefRels ∩ SymRels ) ∩ TrRels ) | ||
Definition | df-eqvrel 35822 | Define the equivalence relation predicate. (Read: 𝑅 is an equivalence relation.) For sets, being an element of the class of equivalence relations (df-eqvrels 35821) is equivalent to satisfying the equivalence relation predicate, see eleqvrelsrel 35831. Alternate definitions are dfeqvrel2 35827 and dfeqvrel3 35828. (Contributed by Peter Mazsa, 17-Apr-2019.) |
⊢ ( EqvRel 𝑅 ↔ ( RefRel 𝑅 ∧ SymRel 𝑅 ∧ TrRel 𝑅)) | ||
Definition | df-coeleqvrels 35823 | Define the the coelement equivalence relations class, the class of sets with coelement equivalence relations. For sets, being an element of the class of coelement equivalence relations is equivalent to satisfying the coelement equivalence relation predicate, see elcoeleqvrelsrel 35833. Alternate definition is dfcoeleqvrels 35858. (Contributed by Peter Mazsa, 28-Nov-2022.) |
⊢ CoElEqvRels = {𝑎 ∣ ≀ (◡ E ↾ 𝑎) ∈ EqvRels } | ||
Definition | df-coeleqvrel 35824 | Define the coelement equivalence relation predicate. (Read: the coelement equivalence relation on 𝐴.) Alternate definition is dfcoeleqvrel 35859. For sets, being an element of the class of coelement equivalence relations is equivalent to satisfying the coelement equivalence relation predicate, see elcoeleqvrelsrel 35833. (Contributed by Peter Mazsa, 11-Dec-2021.) |
⊢ ( CoElEqvRel 𝐴 ↔ EqvRel ≀ (◡ E ↾ 𝐴)) | ||
Theorem | dfeqvrels2 35825 | Alternate definition of the class of equivalence relations. (Contributed by Peter Mazsa, 2-Dec-2019.) |
⊢ EqvRels = {𝑟 ∈ Rels ∣ (( I ↾ dom 𝑟) ⊆ 𝑟 ∧ ◡𝑟 ⊆ 𝑟 ∧ (𝑟 ∘ 𝑟) ⊆ 𝑟)} | ||
Theorem | dfeqvrels3 35826* | Alternate definition of the class of equivalence relations. (Contributed by Peter Mazsa, 2-Dec-2019.) |
⊢ EqvRels = {𝑟 ∈ Rels ∣ (∀𝑥 ∈ dom 𝑟 𝑥𝑟𝑥 ∧ ∀𝑥∀𝑦(𝑥𝑟𝑦 → 𝑦𝑟𝑥) ∧ ∀𝑥∀𝑦∀𝑧((𝑥𝑟𝑦 ∧ 𝑦𝑟𝑧) → 𝑥𝑟𝑧))} | ||
Theorem | dfeqvrel2 35827 | Alternate definition of the equivalence relation predicate. (Contributed by Peter Mazsa, 22-Apr-2019.) |
⊢ ( EqvRel 𝑅 ↔ ((( I ↾ dom 𝑅) ⊆ 𝑅 ∧ ◡𝑅 ⊆ 𝑅 ∧ (𝑅 ∘ 𝑅) ⊆ 𝑅) ∧ Rel 𝑅)) | ||
Theorem | dfeqvrel3 35828* | Alternate definition of the equivalence relation predicate. (Contributed by Peter Mazsa, 22-Apr-2019.) |
⊢ ( EqvRel 𝑅 ↔ ((∀𝑥 ∈ dom 𝑅 𝑥𝑅𝑥 ∧ ∀𝑥∀𝑦(𝑥𝑅𝑦 → 𝑦𝑅𝑥) ∧ ∀𝑥∀𝑦∀𝑧((𝑥𝑅𝑦 ∧ 𝑦𝑅𝑧) → 𝑥𝑅𝑧)) ∧ Rel 𝑅)) | ||
Theorem | eleqvrels2 35829 | Element of the class of equivalence relations. (Contributed by Peter Mazsa, 24-Aug-2021.) |
⊢ (𝑅 ∈ EqvRels ↔ ((( I ↾ dom 𝑅) ⊆ 𝑅 ∧ ◡𝑅 ⊆ 𝑅 ∧ (𝑅 ∘ 𝑅) ⊆ 𝑅) ∧ 𝑅 ∈ Rels )) | ||
Theorem | eleqvrels3 35830* | Element of the class of equivalence relations. (Contributed by Peter Mazsa, 24-Aug-2021.) |
⊢ (𝑅 ∈ EqvRels ↔ ((∀𝑥 ∈ dom 𝑅 𝑥𝑅𝑥 ∧ ∀𝑥∀𝑦(𝑥𝑅𝑦 → 𝑦𝑅𝑥) ∧ ∀𝑥∀𝑦∀𝑧((𝑥𝑅𝑦 ∧ 𝑦𝑅𝑧) → 𝑥𝑅𝑧)) ∧ 𝑅 ∈ Rels )) | ||
Theorem | eleqvrelsrel 35831 | For sets, being an element of the class of equivalence relations is equivalent to satisfying the equivalence relation predicate. (Contributed by Peter Mazsa, 24-Aug-2021.) |
⊢ (𝑅 ∈ 𝑉 → (𝑅 ∈ EqvRels ↔ EqvRel 𝑅)) | ||
Theorem | elcoeleqvrels 35832 | Elementhood in the coelement equivalence relations class. (Contributed by Peter Mazsa, 24-Jul-2023.) |
⊢ (𝐴 ∈ 𝑉 → (𝐴 ∈ CoElEqvRels ↔ ≀ (◡ E ↾ 𝐴) ∈ EqvRels )) | ||
Theorem | elcoeleqvrelsrel 35833 | For sets, being an element of the class of coelement equivalence relations is equivalent to satisfying the coelement equivalence relation predicate. (Contributed by Peter Mazsa, 24-Jul-2023.) |
⊢ (𝐴 ∈ 𝑉 → (𝐴 ∈ CoElEqvRels ↔ CoElEqvRel 𝐴)) | ||
Theorem | eqvrelrel 35834 | An equivalence relation is a relation. (Contributed by Peter Mazsa, 2-Jun-2019.) |
⊢ ( EqvRel 𝑅 → Rel 𝑅) | ||
Theorem | eqvrelrefrel 35835 | An equivalence relation is reflexive. (Contributed by Peter Mazsa, 29-Dec-2021.) |
⊢ ( EqvRel 𝑅 → RefRel 𝑅) | ||
Theorem | eqvrelsymrel 35836 | An equivalence relation is symmetric. (Contributed by Peter Mazsa, 29-Dec-2021.) |
⊢ ( EqvRel 𝑅 → SymRel 𝑅) | ||
Theorem | eqvreltrrel 35837 | An equivalence relation is transitive. (Contributed by Peter Mazsa, 29-Dec-2021.) |
⊢ ( EqvRel 𝑅 → TrRel 𝑅) | ||
Theorem | eqvrelim 35838 | Equivalence relation implies that the domain and the range are equal. (Contributed by Peter Mazsa, 29-Dec-2021.) |
⊢ ( EqvRel 𝑅 → dom 𝑅 = ran 𝑅) | ||
Theorem | eqvreleq 35839 | Equality theorem for equivalence relation. (Contributed by Peter Mazsa, 19-Apr-2020.) (Revised by Peter Mazsa, 23-Sep-2021.) |
⊢ (𝑅 = 𝑆 → ( EqvRel 𝑅 ↔ EqvRel 𝑆)) | ||
Theorem | eqvreleqi 35840 | Equality theorem for equivalence relation, inference version. (Contributed by Peter Mazsa, 23-Sep-2021.) |
⊢ 𝑅 = 𝑆 ⇒ ⊢ ( EqvRel 𝑅 ↔ EqvRel 𝑆) | ||
Theorem | eqvreleqd 35841 | Equality theorem for equivalence relation, deduction version. (Contributed by Peter Mazsa, 23-Sep-2021.) |
⊢ (𝜑 → 𝑅 = 𝑆) ⇒ ⊢ (𝜑 → ( EqvRel 𝑅 ↔ EqvRel 𝑆)) | ||
Theorem | eqvrelsym 35842 | An equivalence relation is symmetric. (Contributed by NM, 4-Jun-1995.) (Revised by Mario Carneiro, 12-Aug-2015.) (Revised by Peter Mazsa, 2-Jun-2019.) |
⊢ (𝜑 → EqvRel 𝑅) & ⊢ (𝜑 → 𝐴𝑅𝐵) ⇒ ⊢ (𝜑 → 𝐵𝑅𝐴) | ||
Theorem | eqvrelsymb 35843 | An equivalence relation is symmetric. (Contributed by NM, 30-Jul-1995.) (Revised by Mario Carneiro, 12-Aug-2015.) (Revised and distinct variable conditions removed by Peter Mazsa, 2-Jun-2019.) |
⊢ (𝜑 → EqvRel 𝑅) ⇒ ⊢ (𝜑 → (𝐴𝑅𝐵 ↔ 𝐵𝑅𝐴)) | ||
Theorem | eqvreltr 35844 | An equivalence relation is transitive. (Contributed by NM, 4-Jun-1995.) (Revised by Mario Carneiro, 12-Aug-2015.) (Revised by Peter Mazsa, 2-Jun-2019.) |
⊢ (𝜑 → EqvRel 𝑅) ⇒ ⊢ (𝜑 → ((𝐴𝑅𝐵 ∧ 𝐵𝑅𝐶) → 𝐴𝑅𝐶)) | ||
Theorem | eqvreltrd 35845 | A transitivity relation for equivalences. (Contributed by Mario Carneiro, 9-Jul-2014.) (Revised by Peter Mazsa, 2-Jun-2019.) |
⊢ (𝜑 → EqvRel 𝑅) & ⊢ (𝜑 → 𝐴𝑅𝐵) & ⊢ (𝜑 → 𝐵𝑅𝐶) ⇒ ⊢ (𝜑 → 𝐴𝑅𝐶) | ||
Theorem | eqvreltr4d 35846 | A transitivity relation for equivalences. (Contributed by Mario Carneiro, 9-Jul-2014.) (Revised by Peter Mazsa, 2-Jun-2019.) |
⊢ (𝜑 → EqvRel 𝑅) & ⊢ (𝜑 → 𝐴𝑅𝐵) & ⊢ (𝜑 → 𝐶𝑅𝐵) ⇒ ⊢ (𝜑 → 𝐴𝑅𝐶) | ||
Theorem | eqvrelref 35847 | An equivalence relation is reflexive on its field. Compare Theorem 3M of [Enderton] p. 56. (Contributed by Mario Carneiro, 6-May-2013.) (Revised by Mario Carneiro, 12-Aug-2015.) (Revised by Peter Mazsa, 2-Jun-2019.) |
⊢ (𝜑 → EqvRel 𝑅) & ⊢ (𝜑 → 𝐴 ∈ dom 𝑅) ⇒ ⊢ (𝜑 → 𝐴𝑅𝐴) | ||
Theorem | eqvrelth 35848 | Basic property of equivalence relations. Theorem 73 of [Suppes] p. 82. (Contributed by NM, 23-Jul-1995.) (Revised by Mario Carneiro, 6-Jul-2015.) (Revised by Peter Mazsa, 2-Jun-2019.) |
⊢ (𝜑 → EqvRel 𝑅) & ⊢ (𝜑 → 𝐴 ∈ dom 𝑅) ⇒ ⊢ (𝜑 → (𝐴𝑅𝐵 ↔ [𝐴]𝑅 = [𝐵]𝑅)) | ||
Theorem | eqvrelcl 35849 | Elementhood in the field of an equivalence relation. (Contributed by Mario Carneiro, 12-Aug-2015.) (Revised by Peter Mazsa, 2-Jun-2019.) |
⊢ (𝜑 → EqvRel 𝑅) & ⊢ (𝜑 → 𝐴𝑅𝐵) ⇒ ⊢ (𝜑 → 𝐴 ∈ dom 𝑅) | ||
Theorem | eqvrelthi 35850 | Basic property of equivalence relations. Part of Lemma 3N of [Enderton] p. 57. (Contributed by NM, 30-Jul-1995.) (Revised by Mario Carneiro, 9-Jul-2014.) (Revised by Peter Mazsa, 2-Jun-2019.) |
⊢ (𝜑 → EqvRel 𝑅) & ⊢ (𝜑 → 𝐴𝑅𝐵) ⇒ ⊢ (𝜑 → [𝐴]𝑅 = [𝐵]𝑅) | ||
Theorem | eqvreldisj 35851 | Equivalence classes do not overlap. In other words, two equivalence classes are either equal or disjoint. Theorem 74 of [Suppes] p. 83. (Contributed by NM, 15-Jun-2004.) (Revised by Mario Carneiro, 9-Jul-2014.) (Revised by Peter Mazsa, 2-Jun-2019.) |
⊢ ( EqvRel 𝑅 → ([𝐴]𝑅 = [𝐵]𝑅 ∨ ([𝐴]𝑅 ∩ [𝐵]𝑅) = ∅)) | ||
Theorem | qsdisjALTV 35852 | Elements of a quotient set do not overlap. (Contributed by Rodolfo Medina, 12-Oct-2010.) (Revised by Mario Carneiro, 11-Jul-2014.) (Revised by Peter Mazsa, 3-Jun-2019.) |
⊢ (𝜑 → EqvRel 𝑅) & ⊢ (𝜑 → 𝐵 ∈ (𝐴 / 𝑅)) & ⊢ (𝜑 → 𝐶 ∈ (𝐴 / 𝑅)) ⇒ ⊢ (𝜑 → (𝐵 = 𝐶 ∨ (𝐵 ∩ 𝐶) = ∅)) | ||
Theorem | eqvrelqsel 35853 | If an element of a quotient set contains a given element, it is equal to the equivalence class of the element. (Contributed by Mario Carneiro, 12-Aug-2015.) (Revised by Peter Mazsa, 28-Dec-2019.) |
⊢ (( EqvRel 𝑅 ∧ 𝐵 ∈ (𝐴 / 𝑅) ∧ 𝐶 ∈ 𝐵) → 𝐵 = [𝐶]𝑅) | ||
Theorem | eqvrelcoss 35854 | Two ways to express equivalent cosets. (Contributed by Peter Mazsa, 4-Jul-2020.) (Revised by Peter Mazsa, 20-Dec-2021.) |
⊢ ( EqvRel ≀ 𝑅 ↔ TrRel ≀ 𝑅) | ||
Theorem | eqvrelcoss3 35855* | Two ways to express equivalent cosets. (Contributed by Peter Mazsa, 28-Apr-2019.) |
⊢ ( EqvRel ≀ 𝑅 ↔ ∀𝑥∀𝑦∀𝑧((𝑥 ≀ 𝑅𝑦 ∧ 𝑦 ≀ 𝑅𝑧) → 𝑥 ≀ 𝑅𝑧)) | ||
Theorem | eqvrelcoss2 35856 | Two ways to express equivalent cosets. (Contributed by Peter Mazsa, 3-May-2019.) |
⊢ ( EqvRel ≀ 𝑅 ↔ ≀ ≀ 𝑅 ⊆ ≀ 𝑅) | ||
Theorem | eqvrelcoss4 35857* | Two ways to express equivalent cosets. (Contributed by Peter Mazsa, 3-May-2019.) (Revised by Peter Mazsa, 30-Sep-2021.) |
⊢ ( EqvRel ≀ 𝑅 ↔ ∀𝑥∀𝑧(([𝑥] ≀ 𝑅 ∩ [𝑧] ≀ 𝑅) ≠ ∅ → ([𝑥]◡𝑅 ∩ [𝑧]◡𝑅) ≠ ∅)) | ||
Theorem | dfcoeleqvrels 35858 | Alternate definition of the coelement equivalence relations class. Other alternate definitions should be based on eqvrelcoss2 35856, eqvrelcoss3 35855 and eqvrelcoss4 35857 when needed. (Contributed by Peter Mazsa, 28-Nov-2022.) |
⊢ CoElEqvRels = {𝑎 ∣ ∼ 𝑎 ∈ EqvRels } | ||
Theorem | dfcoeleqvrel 35859 | Alternate definition of the coelement equivalence relation predicate: a coelement equivalence relation is an equivalence relation on coelements. Other alternate definitions should be based on eqvrelcoss2 35856, eqvrelcoss3 35855 and eqvrelcoss4 35857 when needed. (Contributed by Peter Mazsa, 28-Nov-2022.) |
⊢ ( CoElEqvRel 𝐴 ↔ EqvRel ∼ 𝐴) | ||
Definition | df-redunds 35860* | Define the class of all redundant sets 𝑥 with respect to 𝑦 in 𝑧. For sets, binary relation on the class of all redundant sets (brredunds 35863) is equivalent to satisfying the redundancy predicate (df-redund 35861). (Contributed by Peter Mazsa, 23-Oct-2022.) |
⊢ Redunds = ◡{〈〈𝑦, 𝑧〉, 𝑥〉 ∣ (𝑥 ⊆ 𝑦 ∧ (𝑥 ∩ 𝑧) = (𝑦 ∩ 𝑧))} | ||
Definition | df-redund 35861 | Define the redundancy predicate. Read: 𝐴 is redundant with respect to 𝐵 in 𝐶. For sets, binary relation on the class of all redundant sets (brredunds 35863) is equivalent to satisfying the redundancy predicate. (Contributed by Peter Mazsa, 23-Oct-2022.) |
⊢ (𝐴 Redund 〈𝐵, 𝐶〉 ↔ (𝐴 ⊆ 𝐵 ∧ (𝐴 ∩ 𝐶) = (𝐵 ∩ 𝐶))) | ||
Definition | df-redundp 35862 | Define the redundancy operator for propositions, cf. df-redund 35861. (Contributed by Peter Mazsa, 23-Oct-2022.) |
⊢ ( redund (𝜑, 𝜓, 𝜒) ↔ ((𝜑 → 𝜓) ∧ ((𝜑 ∧ 𝜒) ↔ (𝜓 ∧ 𝜒)))) | ||
Theorem | brredunds 35863 | Binary relation on the class of all redundant sets. (Contributed by Peter Mazsa, 25-Oct-2022.) |
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊 ∧ 𝐶 ∈ 𝑋) → (𝐴 Redunds 〈𝐵, 𝐶〉 ↔ (𝐴 ⊆ 𝐵 ∧ (𝐴 ∩ 𝐶) = (𝐵 ∩ 𝐶)))) | ||
Theorem | brredundsredund 35864 | For sets, binary relation on the class of all redundant sets (brredunds 35863) is equivalent to satisfying the redundancy predicate (df-redund 35861). (Contributed by Peter Mazsa, 25-Oct-2022.) |
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊 ∧ 𝐶 ∈ 𝑋) → (𝐴 Redunds 〈𝐵, 𝐶〉 ↔ 𝐴 Redund 〈𝐵, 𝐶〉)) | ||
Theorem | redundss3 35865 | Implication of redundancy predicate. (Contributed by Peter Mazsa, 26-Oct-2022.) |
⊢ 𝐷 ⊆ 𝐶 ⇒ ⊢ (𝐴 Redund 〈𝐵, 𝐶〉 → 𝐴 Redund 〈𝐵, 𝐷〉) | ||
Theorem | redundeq1 35866 | Equivalence of redundancy predicates. (Contributed by Peter Mazsa, 26-Oct-2022.) |
⊢ 𝐴 = 𝐷 ⇒ ⊢ (𝐴 Redund 〈𝐵, 𝐶〉 ↔ 𝐷 Redund 〈𝐵, 𝐶〉) | ||
Theorem | redundpim3 35867 | Implication of redundancy of proposition. (Contributed by Peter Mazsa, 26-Oct-2022.) |
⊢ (𝜃 → 𝜒) ⇒ ⊢ ( redund (𝜑, 𝜓, 𝜒) → redund (𝜑, 𝜓, 𝜃)) | ||
Theorem | redundpbi1 35868 | Equivalence of redundancy of propositions. (Contributed by Peter Mazsa, 25-Oct-2022.) |
⊢ (𝜑 ↔ 𝜃) ⇒ ⊢ ( redund (𝜑, 𝜓, 𝜒) ↔ redund (𝜃, 𝜓, 𝜒)) | ||
Theorem | refrelsredund4 35869 | The naive version of the class of reflexive relations is redundant with respect to the class of reflexive relations (see dfrefrels2 35755) if the relations are symmetric as well. (Contributed by Peter Mazsa, 26-Oct-2022.) |
⊢ {𝑟 ∈ Rels ∣ ( I ↾ dom 𝑟) ⊆ 𝑟} Redund 〈 RefRels , ( RefRels ∩ SymRels )〉 | ||
Theorem | refrelsredund2 35870 | The naive version of the class of reflexive relations is redundant with respect to the class of reflexive relations (see dfrefrels2 35755) in the class of equivalence relations. (Contributed by Peter Mazsa, 26-Oct-2022.) |
⊢ {𝑟 ∈ Rels ∣ ( I ↾ dom 𝑟) ⊆ 𝑟} Redund 〈 RefRels , EqvRels 〉 | ||
Theorem | refrelsredund3 35871* | The naive version of the class of reflexive relations {𝑟 ∈ Rels ∣ ∀𝑥 ∈ dom 𝑟𝑥𝑟𝑥} is redundant with respect to the class of reflexive relations (see dfrefrels3 35756) in the class of equivalence relations. (Contributed by Peter Mazsa, 26-Oct-2022.) |
⊢ {𝑟 ∈ Rels ∣ ∀𝑥 ∈ dom 𝑟 𝑥𝑟𝑥} Redund 〈 RefRels , EqvRels 〉 | ||
Theorem | refrelredund4 35872 | The naive version of the definition of reflexive relation is redundant with respect to reflexive relation (see dfrefrel2 35757) if the relation is symmetric as well. (Contributed by Peter Mazsa, 26-Oct-2022.) |
⊢ redund ((( I ↾ dom 𝑅) ⊆ 𝑅 ∧ Rel 𝑅), RefRel 𝑅, ( RefRel 𝑅 ∧ SymRel 𝑅)) | ||
Theorem | refrelredund2 35873 | The naive version of the definition of reflexive relation is redundant with respect to reflexive relation (see dfrefrel2 35757) in equivalence relation. (Contributed by Peter Mazsa, 25-Oct-2022.) |
⊢ redund ((( I ↾ dom 𝑅) ⊆ 𝑅 ∧ Rel 𝑅), RefRel 𝑅, EqvRel 𝑅) | ||
Theorem | refrelredund3 35874* | The naive version of the definition of reflexive relation (∀𝑥 ∈ dom 𝑅𝑥𝑅𝑥 ∧ Rel 𝑅) is redundant with respect to reflexive relation (see dfrefrel3 35758) in equivalence relation. (Contributed by Peter Mazsa, 25-Oct-2022.) |
⊢ redund ((∀𝑥 ∈ dom 𝑅 𝑥𝑅𝑥 ∧ Rel 𝑅), RefRel 𝑅, EqvRel 𝑅) | ||
Definition | df-dmqss 35875* | Define the class of domain quotients. Domain quotients are pairs of sets, typically a relation and a set, where the quotient (see df-qs 8297) of the relation on its domain is equal to the set. See comments of df-ers 35899 for the motivation for this definition. (Contributed by Peter Mazsa, 16-Apr-2019.) |
⊢ DomainQss = {〈𝑥, 𝑦〉 ∣ (dom 𝑥 / 𝑥) = 𝑦} | ||
Definition | df-dmqs 35876 | Define the domain quotient predicate. (Read: the domain quotient of 𝑅 is 𝐴.) If 𝐴 and 𝑅 are sets, the domain quotient binary relation and the domain quotient predicate are the same, see brdmqssqs 35884. (Contributed by Peter Mazsa, 9-Aug-2021.) |
⊢ (𝑅 DomainQs 𝐴 ↔ (dom 𝑅 / 𝑅) = 𝐴) | ||
Theorem | dmqseq 35877 | Equality theorem for domain quotient. (Contributed by Peter Mazsa, 17-Apr-2019.) |
⊢ (𝑅 = 𝑆 → (dom 𝑅 / 𝑅) = (dom 𝑆 / 𝑆)) | ||
Theorem | dmqseqi 35878 | Equality theorem for domain quotient, inference version. (Contributed by Peter Mazsa, 26-Sep-2021.) |
⊢ 𝑅 = 𝑆 ⇒ ⊢ (dom 𝑅 / 𝑅) = (dom 𝑆 / 𝑆) | ||
Theorem | dmqseqd 35879 | Equality theorem for domain quotient set, deduction version. (Contributed by Peter Mazsa, 23-Apr-2021.) |
⊢ (𝜑 → 𝑅 = 𝑆) ⇒ ⊢ (𝜑 → (dom 𝑅 / 𝑅) = (dom 𝑆 / 𝑆)) | ||
Theorem | dmqseqeq1 35880 | Equality theorem for domain quotient. (Contributed by Peter Mazsa, 17-Apr-2019.) |
⊢ (𝑅 = 𝑆 → ((dom 𝑅 / 𝑅) = 𝐴 ↔ (dom 𝑆 / 𝑆) = 𝐴)) | ||
Theorem | dmqseqeq1i 35881 | Equality theorem for domain quotient, inference version. (Contributed by Peter Mazsa, 26-Sep-2021.) |
⊢ 𝑅 = 𝑆 ⇒ ⊢ ((dom 𝑅 / 𝑅) = 𝐴 ↔ (dom 𝑆 / 𝑆) = 𝐴) | ||
Theorem | dmqseqeq1d 35882 | Equality theorem for domain quotient set, deduction version. (Contributed by Peter Mazsa, 26-Sep-2021.) |
⊢ (𝜑 → 𝑅 = 𝑆) ⇒ ⊢ (𝜑 → ((dom 𝑅 / 𝑅) = 𝐴 ↔ (dom 𝑆 / 𝑆) = 𝐴)) | ||
Theorem | brdmqss 35883 | The domain quotient binary relation. (Contributed by Peter Mazsa, 17-Apr-2019.) |
⊢ ((𝐴 ∈ 𝑉 ∧ 𝑅 ∈ 𝑊) → (𝑅 DomainQss 𝐴 ↔ (dom 𝑅 / 𝑅) = 𝐴)) | ||
Theorem | brdmqssqs 35884 | If 𝐴 and 𝑅 are sets, the domain quotient binary relation and the domain quotient predicate are the same. (Contributed by Peter Mazsa, 14-Aug-2021.) |
⊢ ((𝐴 ∈ 𝑉 ∧ 𝑅 ∈ 𝑊) → (𝑅 DomainQss 𝐴 ↔ 𝑅 DomainQs 𝐴)) | ||
Theorem | n0eldmqs 35885 | The empty set is not an element of a domain quotient. (Contributed by Peter Mazsa, 2-Mar-2018.) |
⊢ ¬ ∅ ∈ (dom 𝑅 / 𝑅) | ||
Theorem | n0eldmqseq 35886 | The empty set is not an element of a domain quotient. (Contributed by Peter Mazsa, 3-Nov-2018.) |
⊢ ((dom 𝑅 / 𝑅) = 𝐴 → ¬ ∅ ∈ 𝐴) | ||
Theorem | n0el3 35887 | Two ways of expressing that the empty set is not an element of a class. (Contributed by Peter Mazsa, 27-May-2021.) |
⊢ (¬ ∅ ∈ 𝐴 ↔ (dom (◡ E ↾ 𝐴) / (◡ E ↾ 𝐴)) = 𝐴) | ||
Theorem | cnvepresdmqss 35888 | The domain quotient binary relation of the restricted converse epsilon relation is equivalent to the negated elementhood of the empty set in the restriction. (Contributed by Peter Mazsa, 14-Aug-2021.) |
⊢ (𝐴 ∈ 𝑉 → ((◡ E ↾ 𝐴) DomainQss 𝐴 ↔ ¬ ∅ ∈ 𝐴)) | ||
Theorem | cnvepresdmqs 35889 | The domain quotient predicate for the restricted converse epsilon relation is equivalent to the negated elementhood of the empty set in the restriction. (Contributed by Peter Mazsa, 14-Aug-2021.) |
⊢ ((◡ E ↾ 𝐴) DomainQs 𝐴 ↔ ¬ ∅ ∈ 𝐴) | ||
Theorem | unidmqs 35890 | The range of a relation is equal to the union of the domain quotient. (Contributed by Peter Mazsa, 13-Oct-2018.) |
⊢ (𝑅 ∈ 𝑉 → (Rel 𝑅 → ∪ (dom 𝑅 / 𝑅) = ran 𝑅)) | ||
Theorem | unidmqseq 35891 | The union of the domain quotient of a relation is equal to the class 𝐴 if and only if the range is equal to it as well. (Contributed by Peter Mazsa, 21-Apr-2019.) (Revised by Peter Mazsa, 28-Dec-2021.) |
⊢ (𝑅 ∈ 𝑉 → (Rel 𝑅 → (∪ (dom 𝑅 / 𝑅) = 𝐴 ↔ ran 𝑅 = 𝐴))) | ||
Theorem | dmqseqim 35892 | If the domain quotient of a relation is equal to the class 𝐴, then the range of the relation is the union of the class. (Contributed by Peter Mazsa, 29-Dec-2021.) |
⊢ (𝑅 ∈ 𝑉 → (Rel 𝑅 → ((dom 𝑅 / 𝑅) = 𝐴 → ran 𝑅 = ∪ 𝐴))) | ||
Theorem | dmqseqim2 35893 | Lemma for erim2 35913. (Contributed by Peter Mazsa, 29-Dec-2021.) |
⊢ (𝑅 ∈ 𝑉 → (Rel 𝑅 → ((dom 𝑅 / 𝑅) = 𝐴 → (𝐵 ∈ ran 𝑅 ↔ 𝐵 ∈ ∪ 𝐴)))) | ||
Theorem | releldmqs 35894* | Elementhood in the domain quotient of a relation. (Contributed by Peter Mazsa, 24-Apr-2021.) |
⊢ (𝐴 ∈ 𝑉 → (Rel 𝑅 → (𝐴 ∈ (dom 𝑅 / 𝑅) ↔ ∃𝑢 ∈ dom 𝑅∃𝑥 ∈ [ 𝑢]𝑅𝐴 = [𝑢]𝑅))) | ||
Theorem | eldmqs1cossres 35895* | Elementhood in the domain quotient of the class of cosets by a restriction. (Contributed by Peter Mazsa, 4-May-2019.) |
⊢ (𝐵 ∈ 𝑉 → (𝐵 ∈ (dom ≀ (𝑅 ↾ 𝐴) / ≀ (𝑅 ↾ 𝐴)) ↔ ∃𝑢 ∈ 𝐴 ∃𝑥 ∈ [ 𝑢]𝑅𝐵 = [𝑥] ≀ (𝑅 ↾ 𝐴))) | ||
Theorem | releldmqscoss 35896* | Elementhood in the domain quotient of the class of cosets by a relation. (Contributed by Peter Mazsa, 23-Apr-2021.) |
⊢ (𝐴 ∈ 𝑉 → (Rel 𝑅 → (𝐴 ∈ (dom ≀ 𝑅 / ≀ 𝑅) ↔ ∃𝑢 ∈ dom 𝑅∃𝑥 ∈ [ 𝑢]𝑅𝐴 = [𝑥] ≀ 𝑅))) | ||
Theorem | dmqscoelseq 35897 | Two ways to express the equality of the domain quotient of the coelements on the class 𝐴 with the class 𝐴. (Contributed by Peter Mazsa, 26-Sep-2021.) |
⊢ ((dom ∼ 𝐴 / ∼ 𝐴) = 𝐴 ↔ (∪ 𝐴 / ∼ 𝐴) = 𝐴) | ||
Theorem | dmqs1cosscnvepreseq 35898 | Two ways to express the equality of the domain quotient of the coelements on the class 𝐴 with the class 𝐴. (Contributed by Peter Mazsa, 26-Sep-2021.) |
⊢ ((dom ≀ (◡ E ↾ 𝐴) / ≀ (◡ E ↾ 𝐴)) = 𝐴 ↔ (∪ 𝐴 / ∼ 𝐴) = 𝐴) | ||
Definition | df-ers 35899 |
Define the class of equivalence relations on domain quotients (or: domain
quotients restricted to equivalence relations).
The present definition of equivalence relation in set.mm df-er 8291 "is not standard", "somewhat cryptic", has no costant 0-ary class and does not follow the traditional transparent reflexive-symmetric-transitive relation way of definition of equivalence. The definitions df-eqvrels 35821, dfeqvrels2 35825, dfeqvrels3 35826 and df-eqvrel 35822, dfeqvrel2 35827, dfeqvrel3 35828 are fully transparent in this regard. However, they lack the domain component (dom 𝑅 = 𝐴) of the present df-er 8291. While we acknowledge the need of a domain component, the present df-er 8291 definition does not utilize the results revealed by the new theorems in the Partition-Equivalence Theorem part below (like ~? pets and ~? pet ). From those theorems follows that the natural domain of equivalence relations is not 𝑅Domain𝐴 (i.e. dom 𝑅 = 𝐴 see brdomaing 33398), but 𝑅 DomainQss 𝐴 (i.e. (dom 𝑅 / 𝑅) = 𝐴, see brdmqss 35883), see erim 35914 vs. prter3 36020. While I'm sure we need both equivalence relation df-eqvrels 35821 and equivalence relation on domain quotient df-ers 35899, I'm not sure whether we need a third equivalence relation concept with the present dom 𝑅 = 𝐴 component as well: this needs further investigation. As a default I suppose that these two concepts df-eqvrels 35821 and df-ers 35899 are enough and named the predicate version of the one on domain quotient as the alternate version df-erALTV 35900 of the present df-er 8291. (Contributed by Peter Mazsa, 26-Jun-2021.) |
⊢ Ers = ( DomainQss ↾ EqvRels ) | ||
Definition | df-erALTV 35900 | Equivalence relation with natural domain predicate, see also the comment of df-ers 35899. Alternate definition is dferALTV2 35904. Binary equivalence relation with natural domain and the equivalence relation with natural domain predicate are the same when 𝐴 and 𝑅 are sets, see brerser 35912. (Contributed by Peter Mazsa, 12-Aug-2021.) |
⊢ (𝑅 ErALTV 𝐴 ↔ ( EqvRel 𝑅 ∧ 𝑅 DomainQs 𝐴)) |
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