![]() |
Metamath
Proof Explorer Theorem List (p. 383 of 486) | < 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: | ![]() (1-30846) |
![]() (30847-32369) |
![]() (32370-48587) |
Type | Label | Description |
---|---|---|
Statement | ||
Theorem | elrelscnveq 38201 | Two ways of saying a relation is symmetric. (Contributed by Peter Mazsa, 22-Aug-2021.) |
⊢ (𝑅 ∈ Rels → (◡𝑅 ⊆ 𝑅 ↔ ◡𝑅 = 𝑅)) | ||
Theorem | elrelscnveq2 38202* | Two ways of saying a relation is symmetric. (Contributed by Peter Mazsa, 22-Aug-2021.) |
⊢ (𝑅 ∈ Rels → (◡𝑅 = 𝑅 ↔ ∀𝑥∀𝑦(𝑥𝑅𝑦 ↔ 𝑦𝑅𝑥))) | ||
Theorem | elrelscnveq4 38203* | Two ways of saying a relation is symmetric. (Contributed by Peter Mazsa, 22-Aug-2021.) |
⊢ (𝑅 ∈ Rels → (◡𝑅 ⊆ 𝑅 ↔ ∀𝑥∀𝑦(𝑥𝑅𝑦 ↔ 𝑦𝑅𝑥))) | ||
Theorem | cnvelrels 38204 | The converse of a set is an element of the class of relations. (Contributed by Peter Mazsa, 18-Aug-2019.) |
⊢ (𝐴 ∈ 𝑉 → ◡𝐴 ∈ Rels ) | ||
Theorem | cosselrels 38205 | Cosets of sets are elements of the relations class. Implies ⊢ (𝑅 ∈ Rels → ≀ 𝑅 ∈ Rels ). (Contributed by Peter Mazsa, 25-Aug-2021.) |
⊢ (𝐴 ∈ 𝑉 → ≀ 𝐴 ∈ Rels ) | ||
Theorem | cosscnvelrels 38206 | Cosets of converse sets are elements of the relations class. (Contributed by Peter Mazsa, 31-Aug-2021.) |
⊢ (𝐴 ∈ 𝑉 → ≀ ◡𝐴 ∈ Rels ) | ||
Definition | df-ssr 38207* |
Define the subsets class or the class of subset relations. Similar to
definitions of epsilon relation (df-eprel 5577) and identity relation
(df-id 5571) classes. Subset relation class and Scott
Fenton's subset
class df-sset 35691 are the same: S = SSet (compare dfssr2 38208 with
df-sset 35691), the only reason we do not use dfssr2 38208 as the base
definition of the subsets class is the way we defined the epsilon
relation and the identity relation classes.
The binary relation on the class of subsets and the subclass relationship (df-ss 3964) are the same, that is, (𝐴 S 𝐵 ↔ 𝐴 ⊆ 𝐵) when 𝐵 is a set, see brssr 38210. Yet in general we use the subclass relation 𝐴 ⊆ 𝐵 both for classes and for sets, see the comment of df-ss 3964. The only exception (aside from directly investigating the class S e.g. in relssr 38209 or in extssr 38218) is when we have a specific purpose with its usage, like in case of df-refs 38219 versus df-cnvrefs 38234, where we need S to define the class of reflexive sets in order to be able to define the class of converse reflexive sets with the help of the converse of S. The subsets class S has another place in set.mm as well: if we define extensional relation based on the common property in extid 38019, extep 37992 and extssr 38218, then "extrelssr" " |- ExtRel S " is a theorem along with "extrelep" " |- ExtRel E " and "extrelid" " |- ExtRel I " . (Contributed by Peter Mazsa, 25-Jul-2019.) |
⊢ S = {〈𝑥, 𝑦〉 ∣ 𝑥 ⊆ 𝑦} | ||
Theorem | dfssr2 38208 | Alternate definition of the subset relation. (Contributed by Peter Mazsa, 9-Aug-2021.) |
⊢ S = ((V × V) ∖ ran ( E ⋉ (V ∖ E ))) | ||
Theorem | relssr 38209 | The subset relation is a relation. (Contributed by Peter Mazsa, 1-Aug-2019.) |
⊢ Rel S | ||
Theorem | brssr 38210 | The subset relation and subclass relationship (df-ss 3964) are the same, that is, (𝐴 S 𝐵 ↔ 𝐴 ⊆ 𝐵) when 𝐵 is a set. (Contributed by Peter Mazsa, 31-Jul-2019.) |
⊢ (𝐵 ∈ 𝑉 → (𝐴 S 𝐵 ↔ 𝐴 ⊆ 𝐵)) | ||
Theorem | brssrid 38211 | Any set is a subset of itself. (Contributed by Peter Mazsa, 1-Aug-2019.) |
⊢ (𝐴 ∈ 𝑉 → 𝐴 S 𝐴) | ||
Theorem | issetssr 38212 | Two ways of expressing set existence. (Contributed by Peter Mazsa, 1-Aug-2019.) |
⊢ (𝐴 ∈ V ↔ 𝐴 S 𝐴) | ||
Theorem | brssrres 38213 | Restricted subset binary relation. (Contributed by Peter Mazsa, 25-Nov-2019.) |
⊢ (𝐶 ∈ 𝑉 → (𝐵( S ↾ 𝐴)𝐶 ↔ (𝐵 ∈ 𝐴 ∧ 𝐵 ⊆ 𝐶))) | ||
Theorem | br1cnvssrres 38214 | Restricted converse subset binary relation. (Contributed by Peter Mazsa, 25-Nov-2019.) |
⊢ (𝐵 ∈ 𝑉 → (𝐵◡( S ↾ 𝐴)𝐶 ↔ (𝐶 ∈ 𝐴 ∧ 𝐶 ⊆ 𝐵))) | ||
Theorem | brcnvssr 38215 | The converse of a subset relation swaps arguments. (Contributed by Peter Mazsa, 1-Aug-2019.) |
⊢ (𝐴 ∈ 𝑉 → (𝐴◡ S 𝐵 ↔ 𝐵 ⊆ 𝐴)) | ||
Theorem | brcnvssrid 38216 | Any set is a converse subset of itself. (Contributed by Peter Mazsa, 9-Jun-2021.) |
⊢ (𝐴 ∈ 𝑉 → 𝐴◡ S 𝐴) | ||
Theorem | br1cossxrncnvssrres 38217* | 〈𝐵, 𝐶〉 and 〈𝐷, 𝐸〉 are cosets by range Cartesian product with restricted converse subsets class: a binary relation. (Contributed by Peter Mazsa, 9-Jun-2021.) |
⊢ (((𝐵 ∈ 𝑉 ∧ 𝐶 ∈ 𝑊) ∧ (𝐷 ∈ 𝑋 ∧ 𝐸 ∈ 𝑌)) → (〈𝐵, 𝐶〉 ≀ (𝑅 ⋉ (◡ S ↾ 𝐴))〈𝐷, 𝐸〉 ↔ ∃𝑢 ∈ 𝐴 ((𝐶 ⊆ 𝑢 ∧ 𝑢𝑅𝐵) ∧ (𝐸 ⊆ 𝑢 ∧ 𝑢𝑅𝐷)))) | ||
Theorem | extssr 38218 | Property of subset relation, see also extid 38019, extep 37992 and the comment of df-ssr 38207. (Contributed by Peter Mazsa, 10-Jul-2019.) |
⊢ ((𝐴 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → ([𝐴]◡ S = [𝐵]◡ S ↔ 𝐴 = 𝐵)) | ||
Definition | df-refs 38219 |
Define the class of all reflexive sets. It is used only by df-refrels 38220.
We use subset relation S (df-ssr 38207) here to be able to define
converse reflexivity (df-cnvrefs 38234), see also the comment of df-ssr 38207.
The elements of this class are not necessarily relations (versus
df-refrels 38220).
Note the similarity of Definitions df-refs 38219, df-syms 38251 and df-trs 38281, cf. comments of dfrefrels2 38222. (Contributed by Peter Mazsa, 19-Jul-2019.) |
⊢ Refs = {𝑥 ∣ ( I ∩ (dom 𝑥 × ran 𝑥)) S (𝑥 ∩ (dom 𝑥 × ran 𝑥))} | ||
Definition | df-refrels 38220 |
Define the class of reflexive relations. This is practically dfrefrels2 38222
(which reveals that RefRels can not include proper
classes like I
as is elements, see comments of dfrefrels2 38222).
Another alternative definition is dfrefrels3 38223. The element of this class and the reflexive relation predicate (df-refrel 38221) are the same, that is, (𝑅 ∈ RefRels ↔ RefRel 𝑅) when 𝐴 is a set, see elrefrelsrel 38229. This definition is similar to the definitions of the classes of symmetric (df-symrels 38252) and transitive (df-trrels 38282) relations. (Contributed by Peter Mazsa, 7-Jul-2019.) |
⊢ RefRels = ( Refs ∩ Rels ) | ||
Definition | df-refrel 38221 | Define the reflexive relation predicate. (Read: 𝑅 is a reflexive relation.) This is a surprising definition, see the comment of dfrefrel3 38225. Alternate definitions are dfrefrel2 38224 and dfrefrel3 38225. For sets, being an element of the class of reflexive relations (df-refrels 38220) is equivalent to satisfying the reflexive relation predicate, that is (𝑅 ∈ RefRels ↔ RefRel 𝑅) when 𝑅 is a set, see elrefrelsrel 38229. (Contributed by Peter Mazsa, 16-Jul-2021.) |
⊢ ( RefRel 𝑅 ↔ (( I ∩ (dom 𝑅 × ran 𝑅)) ⊆ (𝑅 ∩ (dom 𝑅 × ran 𝑅)) ∧ Rel 𝑅)) | ||
Theorem | dfrefrels2 38222 |
Alternate definition of the class of reflexive relations. This is a 0-ary
class constant, which is recommended for definitions (see the 1.
Guideline at https://us.metamath.org/ileuni/mathbox.html).
Proper
classes (like I, see iprc 7914)
are not elements of this (or any)
class: if a class is an element of another class, it is not a proper class
but a set, see elex 3483. So if we use 0-ary constant classes as our
main
definitions, they are valid only for sets, not for proper classes. For
proper classes we use predicate-type definitions like df-refrel 38221. See
also the comment of df-rels 38194.
Note that while elementhood in the class of relations cancels restriction of 𝑟 in dfrefrels2 38222, it keeps restriction of I: this is why the very similar definitions df-refs 38219, df-syms 38251 and df-trs 38281 diverge when we switch from (general) sets to relations in dfrefrels2 38222, dfsymrels2 38254 and dftrrels2 38284. (Contributed by Peter Mazsa, 20-Jul-2019.) |
⊢ RefRels = {𝑟 ∈ Rels ∣ ( I ∩ (dom 𝑟 × ran 𝑟)) ⊆ 𝑟} | ||
Theorem | dfrefrels3 38223* | Alternate definition of the class of reflexive relations. (Contributed by Peter Mazsa, 8-Jul-2019.) |
⊢ RefRels = {𝑟 ∈ Rels ∣ ∀𝑥 ∈ dom 𝑟∀𝑦 ∈ ran 𝑟(𝑥 = 𝑦 → 𝑥𝑟𝑦)} | ||
Theorem | dfrefrel2 38224 | Alternate definition of the reflexive relation predicate. (Contributed by Peter Mazsa, 25-Jul-2021.) |
⊢ ( RefRel 𝑅 ↔ (( I ∩ (dom 𝑅 × ran 𝑅)) ⊆ 𝑅 ∧ Rel 𝑅)) | ||
Theorem | dfrefrel3 38225* |
Alternate definition of the reflexive relation predicate. A relation is
reflexive iff: for all elements on its domain and range, if an element
of its domain is the same as an element of its range, then there is the
relation between them.
Note that this is definitely not the definition we are accustomed to, like e.g. idref 7150 / idrefALT 6114 or df-reflexive 48548 ⊢ (𝑅Reflexive𝐴 ↔ (𝑅 ⊆ (𝐴 × 𝐴) ∧ ∀𝑥 ∈ 𝐴𝑥𝑅𝑥)). It turns out that the not-surprising definition which contains ∀𝑥 ∈ dom 𝑟𝑥𝑟𝑥 needs symmetry as well, see refsymrels3 38275. Only when this symmetry condition holds, like in case of equivalence relations, see dfeqvrels3 38298, can we write the traditional form ∀𝑥 ∈ dom 𝑟𝑥𝑟𝑥 for reflexive relations. For the special case with square Cartesian product when the two forms are equivalent see idinxpssinxp4 38029 where ⊢ (∀𝑥 ∈ 𝐴∀𝑦 ∈ 𝐴(𝑥 = 𝑦 → 𝑥𝑅𝑦) ↔ ∀𝑥 ∈ 𝐴𝑥𝑅𝑥). See also similar definition of the converse reflexive relations class dfcnvrefrel3 38240. (Contributed by Peter Mazsa, 8-Jul-2019.) |
⊢ ( RefRel 𝑅 ↔ (∀𝑥 ∈ dom 𝑅∀𝑦 ∈ ran 𝑅(𝑥 = 𝑦 → 𝑥𝑅𝑦) ∧ Rel 𝑅)) | ||
Theorem | dfrefrel5 38226* | Alternate definition of the reflexive relation predicate. (Contributed by Peter Mazsa, 12-Dec-2023.) |
⊢ ( RefRel 𝑅 ↔ (∀𝑥 ∈ (dom 𝑅 ∩ ran 𝑅)𝑥𝑅𝑥 ∧ Rel 𝑅)) | ||
Theorem | elrefrels2 38227 | Element of the class of reflexive relations. (Contributed by Peter Mazsa, 23-Jul-2019.) |
⊢ (𝑅 ∈ RefRels ↔ (( I ∩ (dom 𝑅 × ran 𝑅)) ⊆ 𝑅 ∧ 𝑅 ∈ Rels )) | ||
Theorem | elrefrels3 38228* | Element of the class of reflexive relations. (Contributed by Peter Mazsa, 23-Jul-2019.) |
⊢ (𝑅 ∈ RefRels ↔ (∀𝑥 ∈ dom 𝑅∀𝑦 ∈ ran 𝑅(𝑥 = 𝑦 → 𝑥𝑅𝑦) ∧ 𝑅 ∈ Rels )) | ||
Theorem | elrefrelsrel 38229 | For sets, being an element of the class of reflexive relations (df-refrels 38220) is equivalent to satisfying the reflexive relation predicate. (Contributed by Peter Mazsa, 25-Jul-2021.) |
⊢ (𝑅 ∈ 𝑉 → (𝑅 ∈ RefRels ↔ RefRel 𝑅)) | ||
Theorem | refreleq 38230 | Equality theorem for reflexive relation. (Contributed by Peter Mazsa, 15-Apr-2019.) (Revised by Peter Mazsa, 23-Sep-2021.) |
⊢ (𝑅 = 𝑆 → ( RefRel 𝑅 ↔ RefRel 𝑆)) | ||
Theorem | refrelid 38231 | Identity relation is reflexive. (Contributed by Peter Mazsa, 25-Jul-2021.) |
⊢ RefRel I | ||
Theorem | refrelcoss 38232 | The class of cosets by 𝑅 is reflexive. (Contributed by Peter Mazsa, 4-Jul-2020.) |
⊢ RefRel ≀ 𝑅 | ||
Theorem | refrelressn 38233 | Any class ' R ' restricted to the singleton of the set ' A ' (see ressn2 38151) is reflexive. (Contributed by Peter Mazsa, 12-Jun-2024.) |
⊢ (𝐴 ∈ 𝑉 → RefRel (𝑅 ↾ {𝐴})) | ||
Definition | df-cnvrefs 38234 | Define the class of all converse reflexive sets, see the comment of df-ssr 38207. It is used only by df-cnvrefrels 38235. (Contributed by Peter Mazsa, 22-Jul-2019.) |
⊢ CnvRefs = {𝑥 ∣ ( I ∩ (dom 𝑥 × ran 𝑥))◡ S (𝑥 ∩ (dom 𝑥 × ran 𝑥))} | ||
Definition | df-cnvrefrels 38235 |
Define the class of converse reflexive relations. This is practically
dfcnvrefrels2 38237 (which uses the traditional subclass
relation ⊆) :
we use converse subset relation (brcnvssr 38215) here to ensure the
comparability to the definitions of the classes of all reflexive
(df-ref 23495), symmetric (df-syms 38251) and transitive (df-trs 38281) sets.
We use this concept to define functions (df-funsALTV 38390, df-funALTV 38391) and disjoints (df-disjs 38413, df-disjALTV 38414). For sets, being an element of the class of converse reflexive relations is equivalent to satisfying the converse reflexive relation predicate, see elcnvrefrelsrel 38245. Alternate definitions are dfcnvrefrels2 38237 and dfcnvrefrels3 38238. (Contributed by Peter Mazsa, 7-Jul-2019.) |
⊢ CnvRefRels = ( CnvRefs ∩ Rels ) | ||
Definition | df-cnvrefrel 38236 | Define the converse reflexive relation predicate (read: 𝑅 is a converse reflexive relation), see also the comment of dfcnvrefrel3 38240. Alternate definitions are dfcnvrefrel2 38239 and dfcnvrefrel3 38240. (Contributed by Peter Mazsa, 16-Jul-2021.) |
⊢ ( CnvRefRel 𝑅 ↔ ((𝑅 ∩ (dom 𝑅 × ran 𝑅)) ⊆ ( I ∩ (dom 𝑅 × ran 𝑅)) ∧ Rel 𝑅)) | ||
Theorem | dfcnvrefrels2 38237 | Alternate definition of the class of converse reflexive relations. See the comment of dfrefrels2 38222. (Contributed by Peter Mazsa, 21-Jul-2021.) |
⊢ CnvRefRels = {𝑟 ∈ Rels ∣ 𝑟 ⊆ ( I ∩ (dom 𝑟 × ran 𝑟))} | ||
Theorem | dfcnvrefrels3 38238* | Alternate definition of the class of converse reflexive relations. (Contributed by Peter Mazsa, 22-Jul-2019.) |
⊢ CnvRefRels = {𝑟 ∈ Rels ∣ ∀𝑥 ∈ dom 𝑟∀𝑦 ∈ ran 𝑟(𝑥𝑟𝑦 → 𝑥 = 𝑦)} | ||
Theorem | dfcnvrefrel2 38239 | Alternate definition of the converse reflexive relation predicate. (Contributed by Peter Mazsa, 24-Jul-2019.) |
⊢ ( CnvRefRel 𝑅 ↔ (𝑅 ⊆ ( I ∩ (dom 𝑅 × ran 𝑅)) ∧ Rel 𝑅)) | ||
Theorem | dfcnvrefrel3 38240* | Alternate definition of the converse reflexive relation predicate. A relation is converse reflexive iff: for all elements on its domain and range, if for an element of its domain and for an element of its range there is the relation between them, then the two elements are the same, cf. the comment of dfrefrel3 38225. (Contributed by Peter Mazsa, 25-Jul-2021.) |
⊢ ( CnvRefRel 𝑅 ↔ (∀𝑥 ∈ dom 𝑅∀𝑦 ∈ ran 𝑅(𝑥𝑅𝑦 → 𝑥 = 𝑦) ∧ Rel 𝑅)) | ||
Theorem | dfcnvrefrel4 38241 | Alternate definition of the converse reflexive relation predicate. (Contributed by Peter Mazsa, 25-May-2024.) |
⊢ ( CnvRefRel 𝑅 ↔ (𝑅 ⊆ I ∧ Rel 𝑅)) | ||
Theorem | dfcnvrefrel5 38242* | Alternate definition of the converse reflexive relation predicate. (Contributed by Peter Mazsa, 25-May-2024.) |
⊢ ( CnvRefRel 𝑅 ↔ (∀𝑥∀𝑦(𝑥𝑅𝑦 → 𝑥 = 𝑦) ∧ Rel 𝑅)) | ||
Theorem | elcnvrefrels2 38243 | Element of the class of converse reflexive relations. (Contributed by Peter Mazsa, 25-Jul-2019.) |
⊢ (𝑅 ∈ CnvRefRels ↔ (𝑅 ⊆ ( I ∩ (dom 𝑅 × ran 𝑅)) ∧ 𝑅 ∈ Rels )) | ||
Theorem | elcnvrefrels3 38244* | Element of the class of converse reflexive relations. (Contributed by Peter Mazsa, 30-Aug-2021.) |
⊢ (𝑅 ∈ CnvRefRels ↔ (∀𝑥 ∈ dom 𝑅∀𝑦 ∈ ran 𝑅(𝑥𝑅𝑦 → 𝑥 = 𝑦) ∧ 𝑅 ∈ Rels )) | ||
Theorem | elcnvrefrelsrel 38245 | For sets, being an element of the class of converse reflexive relations (df-cnvrefrels 38235) is equivalent to satisfying the converse reflexive relation predicate. (Contributed by Peter Mazsa, 25-Jul-2021.) |
⊢ (𝑅 ∈ 𝑉 → (𝑅 ∈ CnvRefRels ↔ CnvRefRel 𝑅)) | ||
Theorem | cnvrefrelcoss2 38246 | Necessary and sufficient condition for a coset relation to be a converse reflexive relation. (Contributed by Peter Mazsa, 27-Jul-2021.) |
⊢ ( CnvRefRel ≀ 𝑅 ↔ ≀ 𝑅 ⊆ I ) | ||
Theorem | cosselcnvrefrels2 38247 | Necessary and sufficient condition for a coset relation to be an element of the converse reflexive relation class. (Contributed by Peter Mazsa, 25-Aug-2021.) |
⊢ ( ≀ 𝑅 ∈ CnvRefRels ↔ ( ≀ 𝑅 ⊆ I ∧ ≀ 𝑅 ∈ Rels )) | ||
Theorem | cosselcnvrefrels3 38248* | Necessary and sufficient condition for a coset relation to be an element of the converse reflexive relation class. (Contributed by Peter Mazsa, 30-Aug-2021.) |
⊢ ( ≀ 𝑅 ∈ CnvRefRels ↔ (∀𝑢∀𝑥∀𝑦((𝑢𝑅𝑥 ∧ 𝑢𝑅𝑦) → 𝑥 = 𝑦) ∧ ≀ 𝑅 ∈ Rels )) | ||
Theorem | cosselcnvrefrels4 38249* | Necessary and sufficient condition for a coset relation to be an element of the converse reflexive relation class. (Contributed by Peter Mazsa, 31-Aug-2021.) |
⊢ ( ≀ 𝑅 ∈ CnvRefRels ↔ (∀𝑢∃*𝑥 𝑢𝑅𝑥 ∧ ≀ 𝑅 ∈ Rels )) | ||
Theorem | cosselcnvrefrels5 38250* | Necessary and sufficient condition for a coset relation to be an element of the converse reflexive relation class. (Contributed by Peter Mazsa, 5-Sep-2021.) |
⊢ ( ≀ 𝑅 ∈ CnvRefRels ↔ (∀𝑥 ∈ ran 𝑅∀𝑦 ∈ ran 𝑅(𝑥 = 𝑦 ∨ ([𝑥]◡𝑅 ∩ [𝑦]◡𝑅) = ∅) ∧ ≀ 𝑅 ∈ Rels )) | ||
Definition | df-syms 38251 |
Define the class of all symmetric sets. It is used only by df-symrels 38252.
Note the similarity of Definitions df-refs 38219, df-syms 38251 and df-trs 38281, cf. the comment of dfrefrels2 38222. (Contributed by Peter Mazsa, 19-Jul-2019.) |
⊢ Syms = {𝑥 ∣ ◡(𝑥 ∩ (dom 𝑥 × ran 𝑥)) S (𝑥 ∩ (dom 𝑥 × ran 𝑥))} | ||
Definition | df-symrels 38252 |
Define the class of symmetric relations. For sets, being an element of
the class of symmetric relations is equivalent to satisfying the symmetric
relation predicate, see elsymrelsrel 38266. Alternate definitions are
dfsymrels2 38254, dfsymrels3 38255, dfsymrels4 38256 and dfsymrels5 38257.
This definition is similar to the definitions of the classes of reflexive (df-refrels 38220) and transitive (df-trrels 38282) relations. (Contributed by Peter Mazsa, 7-Jul-2019.) |
⊢ SymRels = ( Syms ∩ Rels ) | ||
Definition | df-symrel 38253 | Define the symmetric relation predicate. (Read: 𝑅 is a symmetric relation.) For sets, being an element of the class of symmetric relations (df-symrels 38252) is equivalent to satisfying the symmetric relation predicate, see elsymrelsrel 38266. Alternate definitions are dfsymrel2 38258 and dfsymrel3 38259. (Contributed by Peter Mazsa, 16-Jul-2021.) |
⊢ ( SymRel 𝑅 ↔ (◡(𝑅 ∩ (dom 𝑅 × ran 𝑅)) ⊆ (𝑅 ∩ (dom 𝑅 × ran 𝑅)) ∧ Rel 𝑅)) | ||
Theorem | dfsymrels2 38254 | Alternate definition of the class of symmetric relations. Cf. the comment of dfrefrels2 38222. (Contributed by Peter Mazsa, 20-Jul-2019.) |
⊢ SymRels = {𝑟 ∈ Rels ∣ ◡𝑟 ⊆ 𝑟} | ||
Theorem | dfsymrels3 38255* | Alternate definition of the class of symmetric relations. (Contributed by Peter Mazsa, 22-Jul-2021.) |
⊢ SymRels = {𝑟 ∈ Rels ∣ ∀𝑥∀𝑦(𝑥𝑟𝑦 → 𝑦𝑟𝑥)} | ||
Theorem | dfsymrels4 38256 | Alternate definition of the class of symmetric relations. (Contributed by Peter Mazsa, 20-Jul-2019.) |
⊢ SymRels = {𝑟 ∈ Rels ∣ ◡𝑟 = 𝑟} | ||
Theorem | dfsymrels5 38257* | Alternate definition of the class of symmetric relations. (Contributed by Peter Mazsa, 22-Jul-2021.) |
⊢ SymRels = {𝑟 ∈ Rels ∣ ∀𝑥∀𝑦(𝑥𝑟𝑦 ↔ 𝑦𝑟𝑥)} | ||
Theorem | dfsymrel2 38258 | Alternate definition of the symmetric relation predicate. (Contributed by Peter Mazsa, 19-Apr-2019.) (Revised by Peter Mazsa, 17-Aug-2021.) |
⊢ ( SymRel 𝑅 ↔ (◡𝑅 ⊆ 𝑅 ∧ Rel 𝑅)) | ||
Theorem | dfsymrel3 38259* | Alternate definition of the symmetric relation predicate. (Contributed by Peter Mazsa, 21-Apr-2019.) (Revised by Peter Mazsa, 17-Aug-2021.) |
⊢ ( SymRel 𝑅 ↔ (∀𝑥∀𝑦(𝑥𝑅𝑦 → 𝑦𝑅𝑥) ∧ Rel 𝑅)) | ||
Theorem | dfsymrel4 38260 | Alternate definition of the symmetric relation predicate. (Contributed by Peter Mazsa, 17-Aug-2021.) |
⊢ ( SymRel 𝑅 ↔ (◡𝑅 = 𝑅 ∧ Rel 𝑅)) | ||
Theorem | dfsymrel5 38261* | Alternate definition of the symmetric relation predicate. (Contributed by Peter Mazsa, 17-Aug-2021.) |
⊢ ( SymRel 𝑅 ↔ (∀𝑥∀𝑦(𝑥𝑅𝑦 ↔ 𝑦𝑅𝑥) ∧ Rel 𝑅)) | ||
Theorem | elsymrels2 38262 | Element of the class of symmetric relations. (Contributed by Peter Mazsa, 17-Aug-2021.) |
⊢ (𝑅 ∈ SymRels ↔ (◡𝑅 ⊆ 𝑅 ∧ 𝑅 ∈ Rels )) | ||
Theorem | elsymrels3 38263* | Element of the class of symmetric relations. (Contributed by Peter Mazsa, 17-Aug-2021.) |
⊢ (𝑅 ∈ SymRels ↔ (∀𝑥∀𝑦(𝑥𝑅𝑦 → 𝑦𝑅𝑥) ∧ 𝑅 ∈ Rels )) | ||
Theorem | elsymrels4 38264 | Element of the class of symmetric relations. (Contributed by Peter Mazsa, 17-Aug-2021.) |
⊢ (𝑅 ∈ SymRels ↔ (◡𝑅 = 𝑅 ∧ 𝑅 ∈ Rels )) | ||
Theorem | elsymrels5 38265* | Element of the class of symmetric relations. (Contributed by Peter Mazsa, 17-Aug-2021.) |
⊢ (𝑅 ∈ SymRels ↔ (∀𝑥∀𝑦(𝑥𝑅𝑦 ↔ 𝑦𝑅𝑥) ∧ 𝑅 ∈ Rels )) | ||
Theorem | elsymrelsrel 38266 | For sets, being an element of the class of symmetric relations (df-symrels 38252) is equivalent to satisfying the symmetric relation predicate. (Contributed by Peter Mazsa, 17-Aug-2021.) |
⊢ (𝑅 ∈ 𝑉 → (𝑅 ∈ SymRels ↔ SymRel 𝑅)) | ||
Theorem | symreleq 38267 | Equality theorem for symmetric relation. (Contributed by Peter Mazsa, 15-Apr-2019.) (Revised by Peter Mazsa, 23-Sep-2021.) |
⊢ (𝑅 = 𝑆 → ( SymRel 𝑅 ↔ SymRel 𝑆)) | ||
Theorem | symrelim 38268 | Symmetric relation implies that the domain and the range are equal. (Contributed by Peter Mazsa, 29-Dec-2021.) |
⊢ ( SymRel 𝑅 → dom 𝑅 = ran 𝑅) | ||
Theorem | symrelcoss 38269 | The class of cosets by 𝑅 is symmetric. (Contributed by Peter Mazsa, 20-Dec-2021.) |
⊢ SymRel ≀ 𝑅 | ||
Theorem | idsymrel 38270 | The identity relation is symmetric. (Contributed by AV, 19-Jun-2022.) |
⊢ SymRel I | ||
Theorem | epnsymrel 38271 | The membership (epsilon) relation is not symmetric. (Contributed by AV, 18-Jun-2022.) |
⊢ ¬ SymRel E | ||
Theorem | symrefref2 38272 | Symmetry is a sufficient condition for the equivalence of two versions of the reflexive relation, see also symrefref3 38273. (Contributed by Peter Mazsa, 19-Jul-2018.) |
⊢ (◡𝑅 ⊆ 𝑅 → (( I ∩ (dom 𝑅 × ran 𝑅)) ⊆ 𝑅 ↔ ( I ↾ dom 𝑅) ⊆ 𝑅)) | ||
Theorem | symrefref3 38273* | Symmetry is a sufficient condition for the equivalence of two versions of the reflexive relation, see also symrefref2 38272. (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 38274 | 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 38297) can use the restricted version for their reflexive part (see below), not just the ( I ∩ (dom 𝑟 × ran 𝑟)) ⊆ 𝑟 version of dfrefrels2 38222, cf. the comment of dfrefrels2 38222. (Contributed by Peter Mazsa, 20-Jul-2019.) |
⊢ ( RefRels ∩ SymRels ) = {𝑟 ∈ Rels ∣ (( I ↾ dom 𝑟) ⊆ 𝑟 ∧ ◡𝑟 ⊆ 𝑟)} | ||
Theorem | refsymrels3 38275* | 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 38298) 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 38223, cf. the comment of dfrefrel3 38225. (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 38276 | 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 38224, cf. the comment of dfrefrels2 38222. (Contributed by Peter Mazsa, 23-Aug-2021.) |
⊢ (( RefRel 𝑅 ∧ SymRel 𝑅) ↔ ((( I ↾ dom 𝑅) ⊆ 𝑅 ∧ ◡𝑅 ⊆ 𝑅) ∧ Rel 𝑅)) | ||
Theorem | refsymrel3 38277* | 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 38225, cf. the comment of dfrefrel3 38225. (Contributed by Peter Mazsa, 23-Aug-2021.) |
⊢ (( RefRel 𝑅 ∧ SymRel 𝑅) ↔ ((∀𝑥 ∈ dom 𝑅 𝑥𝑅𝑥 ∧ ∀𝑥∀𝑦(𝑥𝑅𝑦 → 𝑦𝑅𝑥)) ∧ Rel 𝑅)) | ||
Theorem | elrefsymrels2 38278 | 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 38297) can use the restricted version for their reflexive part (see below), not just the ( I ∩ (dom 𝑅 × ran 𝑅)) ⊆ 𝑅 version of dfrefrels2 38222, cf. the comment of dfrefrels2 38222. (Contributed by Peter Mazsa, 22-Jul-2019.) |
⊢ (𝑅 ∈ ( RefRels ∩ SymRels ) ↔ ((( I ↾ dom 𝑅) ⊆ 𝑅 ∧ ◡𝑅 ⊆ 𝑅) ∧ 𝑅 ∈ Rels )) | ||
Theorem | elrefsymrels3 38279* | 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 38298) 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 38223, cf. the comment of dfrefrel3 38225. (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 38280 | 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 38281 |
Define the class of all transitive sets (versus the transitive class
defined in df-tr 5262). It is used only by df-trrels 38282.
Note the similarity of the definitions of df-refs 38219, df-syms 38251 and df-trs 38281. (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 38282 |
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 38290. Alternate definitions
are dftrrels2 38284 and dftrrels3 38285.
This definition is similar to the definitions of the classes of reflexive (df-refrels 38220) and symmetric (df-symrels 38252) relations. (Contributed by Peter Mazsa, 7-Jul-2019.) |
⊢ TrRels = ( Trs ∩ Rels ) | ||
Definition | df-trrel 38283 | Define the transitive relation predicate. (Read: 𝑅 is a transitive relation.) For sets, being an element of the class of transitive relations (df-trrels 38282) is equivalent to satisfying the transitive relation predicate, see eltrrelsrel 38290. Alternate definitions are dftrrel2 38286 and dftrrel3 38287. (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 38284 |
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 5682 (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 38120 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 38285* | 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 38286 | Alternate definition of the transitive relation predicate. (Contributed by Peter Mazsa, 22-Aug-2021.) |
⊢ ( TrRel 𝑅 ↔ ((𝑅 ∘ 𝑅) ⊆ 𝑅 ∧ Rel 𝑅)) | ||
Theorem | dftrrel3 38287* | 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 38288 | Element of the class of transitive relations. (Contributed by Peter Mazsa, 22-Aug-2021.) |
⊢ (𝑅 ∈ TrRels ↔ ((𝑅 ∘ 𝑅) ⊆ 𝑅 ∧ 𝑅 ∈ Rels )) | ||
Theorem | eltrrels3 38289* | 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 38290 | 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 38291 | 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)) | ||
Theorem | trrelressn 38292 | Any class ' R ' restricted to the singleton of the class ' A ' (see ressn2 38151) is transitive. (Contributed by Peter Mazsa, 17-Jun-2024.) |
⊢ TrRel (𝑅 ↾ {𝐴}) | ||
Definition | df-eqvrels 38293 | 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 38303. Alternate definitions are dfeqvrels2 38297 and dfeqvrels3 38298. (Contributed by Peter Mazsa, 7-Nov-2018.) |
⊢ EqvRels = (( RefRels ∩ SymRels ) ∩ TrRels ) | ||
Definition | df-eqvrel 38294 | Define the equivalence relation predicate. (Read: 𝑅 is an equivalence relation.) For sets, being an element of the class of equivalence relations (df-eqvrels 38293) is equivalent to satisfying the equivalence relation predicate, see eleqvrelsrel 38303. Alternate definitions are dfeqvrel2 38299 and dfeqvrel3 38300. (Contributed by Peter Mazsa, 17-Apr-2019.) |
⊢ ( EqvRel 𝑅 ↔ ( RefRel 𝑅 ∧ SymRel 𝑅 ∧ TrRel 𝑅)) | ||
Definition | df-coeleqvrels 38295 | Define 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 38305. Alternate definition is dfcoeleqvrels 38330. (Contributed by Peter Mazsa, 28-Nov-2022.) |
⊢ CoElEqvRels = {𝑎 ∣ ≀ (◡ E ↾ 𝑎) ∈ EqvRels } | ||
Definition | df-coeleqvrel 38296 | Define the coelement equivalence relation predicate. (Read: the coelement equivalence relation on 𝐴.) Alternate definition is dfcoeleqvrel 38331. For sets, being an element of the class of coelement equivalence relations is equivalent to satisfying the coelement equivalence relation predicate, see elcoeleqvrelsrel 38305. (Contributed by Peter Mazsa, 11-Dec-2021.) |
⊢ ( CoElEqvRel 𝐴 ↔ EqvRel ≀ (◡ E ↾ 𝐴)) | ||
Theorem | dfeqvrels2 38297 | 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 38298* | 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 38299 | 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 38300* | 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)) |
< Previous Next > |
Copyright terms: Public domain | < Previous Next > |