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Type | Label | Description |
---|---|---|
Statement | ||
Theorem | prmo5 16201 | The primorial of 5. (Contributed by AV, 28-Aug-2020.) |
⊢ (#p‘5) = ;30 | ||
Theorem | prmo6 16202 | The primorial of 6. (Contributed by AV, 28-Aug-2020.) |
⊢ (#p‘6) = ;30 | ||
Theorem | 1259lem1 16203 | Lemma for 1259prm 16208. Calculate a power mod. In decimal, we calculate 2↑16 = 52𝑁 + 68≡68 and 2↑17≡68 · 2 = 136 in this lemma. (Contributed by Mario Carneiro, 22-Feb-2014.) (Revised by Mario Carneiro, 20-Apr-2015.) (Proof shortened by AV, 16-Sep-2021.) |
⊢ 𝑁 = ;;;1259 ⇒ ⊢ ((2↑;17) mod 𝑁) = (;;136 mod 𝑁) | ||
Theorem | 1259lem2 16204 | Lemma for 1259prm 16208. Calculate a power mod. In decimal, we calculate 2↑34 = (2↑17)↑2≡136↑2≡14𝑁 + 870. (Contributed by Mario Carneiro, 22-Feb-2014.) (Revised by Mario Carneiro, 20-Apr-2015.) (Proof shortened by AV, 15-Sep-2021.) |
⊢ 𝑁 = ;;;1259 ⇒ ⊢ ((2↑;34) mod 𝑁) = (;;870 mod 𝑁) | ||
Theorem | 1259lem3 16205 | Lemma for 1259prm 16208. Calculate a power mod. In decimal, we calculate 2↑38 = 2↑34 · 2↑4≡870 · 16 = 11𝑁 + 71 and 2↑76 = (2↑34)↑2≡71↑2 = 4𝑁 + 5≡5. (Contributed by Mario Carneiro, 22-Feb-2014.) (Revised by Mario Carneiro, 20-Apr-2015.) (Proof shortened by AV, 16-Sep-2021.) |
⊢ 𝑁 = ;;;1259 ⇒ ⊢ ((2↑;76) mod 𝑁) = (5 mod 𝑁) | ||
Theorem | 1259lem4 16206 | Lemma for 1259prm 16208. Calculate a power mod. In decimal, we calculate 2↑306 = (2↑76)↑4 · 4≡5↑4 · 4 = 2𝑁 − 18, 2↑612 = (2↑306)↑2≡18↑2 = 324, 2↑629 = 2↑612 · 2↑17≡324 · 136 = 35𝑁 − 1 and finally 2↑(𝑁 − 1) = (2↑629)↑2≡1↑2 = 1. (Contributed by Mario Carneiro, 22-Feb-2014.) (Revised by Mario Carneiro, 20-Apr-2015.) (Proof shortened by AV, 16-Sep-2021.) |
⊢ 𝑁 = ;;;1259 ⇒ ⊢ ((2↑(𝑁 − 1)) mod 𝑁) = (1 mod 𝑁) | ||
Theorem | 1259lem5 16207 | Lemma for 1259prm 16208. Calculate the GCD of 2↑34 − 1≡869 with 𝑁 = 1259. (Contributed by Mario Carneiro, 22-Feb-2014.) (Revised by Mario Carneiro, 20-Apr-2015.) |
⊢ 𝑁 = ;;;1259 ⇒ ⊢ (((2↑;34) − 1) gcd 𝑁) = 1 | ||
Theorem | 1259prm 16208 | 1259 is a prime number. (Contributed by Mario Carneiro, 22-Feb-2014.) (Proof shortened by Mario Carneiro, 20-Apr-2015.) |
⊢ 𝑁 = ;;;1259 ⇒ ⊢ 𝑁 ∈ ℙ | ||
Theorem | 2503lem1 16209 | Lemma for 2503prm 16212. Calculate a power mod. In decimal, we calculate 2↑18 = 512↑2 = 104𝑁 + 1832≡1832. (Contributed by Mario Carneiro, 3-Mar-2014.) (Revised by Mario Carneiro, 20-Apr-2015.) (Proof shortened by AV, 16-Sep-2021.) |
⊢ 𝑁 = ;;;2503 ⇒ ⊢ ((2↑;18) mod 𝑁) = (;;;1832 mod 𝑁) | ||
Theorem | 2503lem2 16210 | Lemma for 2503prm 16212. Calculate a power mod. We calculate 2↑19 = 2↑18 · 2≡1832 · 2 = 𝑁 + 1161, 2↑38 = (2↑19)↑2≡1161↑2 = 538𝑁 + 1307, 2↑39 = 2↑38 · 2≡1307 · 2 = 𝑁 + 111, 2↑78 = (2↑39)↑2≡111↑2 = 5𝑁 − 194, 2↑156 = (2↑78)↑2≡194↑2 = 15𝑁 + 91, 2↑312 = (2↑156)↑2≡91↑2 = 3𝑁 + 772, 2↑624 = (2↑312)↑2≡772↑2 = 238𝑁 + 270, 2↑1248 = (2↑624)↑2≡270↑2 = 29𝑁 + 313, 2↑1251 = 2↑1248 · 8≡313 · 8 = 𝑁 + 1 and finally 2↑(𝑁 − 1) = (2↑1251)↑2≡1↑2 = 1. (Contributed by Mario Carneiro, 3-Mar-2014.) (Revised by Mario Carneiro, 20-Apr-2015.) (Proof shortened by AV, 16-Sep-2021.) |
⊢ 𝑁 = ;;;2503 ⇒ ⊢ ((2↑(𝑁 − 1)) mod 𝑁) = (1 mod 𝑁) | ||
Theorem | 2503lem3 16211 | Lemma for 2503prm 16212. Calculate the GCD of 2↑18 − 1≡1831 with 𝑁 = 2503. (Contributed by Mario Carneiro, 3-Mar-2014.) (Revised by Mario Carneiro, 20-Apr-2015.) (Proof shortened by AV, 15-Sep-2021.) |
⊢ 𝑁 = ;;;2503 ⇒ ⊢ (((2↑;18) − 1) gcd 𝑁) = 1 | ||
Theorem | 2503prm 16212 | 2503 is a prime number. (Contributed by Mario Carneiro, 3-Mar-2014.) (Proof shortened by Mario Carneiro, 20-Apr-2015.) |
⊢ 𝑁 = ;;;2503 ⇒ ⊢ 𝑁 ∈ ℙ | ||
Theorem | 4001lem1 16213 | Lemma for 4001prm 16217. Calculate a power mod. In decimal, we calculate 2↑12 = 4096 = 𝑁 + 95, 2↑24 = (2↑12)↑2≡95↑2 = 2𝑁 + 1023, 2↑25 = 2↑24 · 2≡1023 · 2 = 2046, 2↑50 = (2↑25)↑2≡2046↑2 = 1046𝑁 + 1070, 2↑100 = (2↑50)↑2≡1070↑2 = 286𝑁 + 614 and 2↑200 = (2↑100)↑2≡614↑2 = 94𝑁 + 902 ≡902. (Contributed by Mario Carneiro, 3-Mar-2014.) (Revised by Mario Carneiro, 20-Apr-2015.) (Proof shortened by AV, 16-Sep-2021.) |
⊢ 𝑁 = ;;;4001 ⇒ ⊢ ((2↑;;200) mod 𝑁) = (;;902 mod 𝑁) | ||
Theorem | 4001lem2 16214 | Lemma for 4001prm 16217. Calculate a power mod. In decimal, we calculate 2↑400 = (2↑200)↑2≡902↑2 = 203𝑁 + 1401 and 2↑800 = (2↑400)↑2≡1401↑2 = 490𝑁 + 2311 ≡2311. (Contributed by Mario Carneiro, 3-Mar-2014.) (Revised by Mario Carneiro, 20-Apr-2015.) (Proof shortened by AV, 16-Sep-2021.) |
⊢ 𝑁 = ;;;4001 ⇒ ⊢ ((2↑;;800) mod 𝑁) = (;;;2311 mod 𝑁) | ||
Theorem | 4001lem3 16215 | Lemma for 4001prm 16217. Calculate a power mod. In decimal, we calculate 2↑1000 = 2↑800 · 2↑200≡2311 · 902 = 521𝑁 + 1 and finally 2↑(𝑁 − 1) = (2↑1000)↑4≡1↑4 = 1. (Contributed by Mario Carneiro, 3-Mar-2014.) (Revised by Mario Carneiro, 20-Apr-2015.) (Proof shortened by AV, 16-Sep-2021.) |
⊢ 𝑁 = ;;;4001 ⇒ ⊢ ((2↑(𝑁 − 1)) mod 𝑁) = (1 mod 𝑁) | ||
Theorem | 4001lem4 16216 | Lemma for 4001prm 16217. Calculate the GCD of 2↑800 − 1≡2310 with 𝑁 = 4001. (Contributed by Mario Carneiro, 3-Mar-2014.) (Revised by Mario Carneiro, 20-Apr-2015.) (Proof shortened by AV, 16-Sep-2021.) |
⊢ 𝑁 = ;;;4001 ⇒ ⊢ (((2↑;;800) − 1) gcd 𝑁) = 1 | ||
Theorem | 4001prm 16217 | 4001 is a prime number. (Contributed by Mario Carneiro, 3-Mar-2014.) (Proof shortened by Mario Carneiro, 20-Apr-2015.) (Proof shortened by AV, 16-Sep-2021.) |
⊢ 𝑁 = ;;;4001 ⇒ ⊢ 𝑁 ∈ ℙ | ||
An "extensible structure" (or "structure" in short, at least in this section) is used to define a specific group, ring, poset, and so on. An extensible structure can contain many components. For example, a group will have at least two components (base set and operation), although it can be further specialized by adding other components such as a multiplicative operation for rings (and still remain a group per our definition). Thus, every ring is also a group. This extensible structure approach allows theorems from more general structures (such as groups) to be reused for more specialized structures (such as rings) without having to reprove anything. Structures are common in mathematics, but in informal (natural language) proofs the details are assumed in ways that we must make explicit. An extensible structure is implemented as a function (a set of ordered pairs) on a finite (and not necessarily sequential) subset of ℕ. The function's argument is the index of a structure component (such as 1 for the base set of a group), and its value is the component (such as the base set). By convention, we normally avoid direct reference to the hard-coded numeric index and instead use structure component extractors such as ndxid 16248 and strfv 16270. Using extractors makes it easier to change numeric indices and also makes the components' purpose clearer. For example, as noted in ndxid 16248, we can refer to a specific poset with base set 𝐵 and order relation 𝐿 using the extensible structure {〈(Base‘ndx), 𝐵〉, 〈(le‘ndx), 𝐿〉} rather than {〈1, 𝐵〉, 〈;10, 𝐿〉}. There are many other possible ways to handle structures. We chose this extensible structure approach because this approach (1) results in simpler notation than other approaches we are aware of, and (2) is easier to do proofs with. We cannot use an approach that uses "hidden" arguments; Metamath does not support hidden arguments, and in any case we want nothing hidden. It would be possible to use a categorical approach (e.g., something vaguely similar to Lean's mathlib). However, instances (the chain of proofs that an 𝑋 is a 𝑌 via a bunch of forgetful functors) can cause serious performance problems for automated tooling, and the resulting proofs would be painful to look at directly (in the case of Lean, they are long past the level where people would find it acceptable to look at them directly). Metamath is working under much stricter conditions than this, and it has still managed to achieve about the same level of flexibility through this "extensible structure" approach. To create a substructure of a given extensible structure, you can simply use the multifunction restriction operator for extensible structures ↾s as defined in df-ress 16230. This can be used to turn statements about rings into statements about subrings, modules into submodules, etc. This definition knows nothing about individual structures and merely truncates the Base set while leaving operators alone. Individual kinds of structures will need to handle this behavior by ignoring operators' values outside the range (like Ring), defining a function using the base set and applying that (like TopGrp), or explicitly truncating the slot before use (like MetSp). For example, the unital ring of integers ℤring is defined in df-zring 20179 as simply ℤring = (ℂfld ↾s ℤ). This can be similarly done for all other subsets of ℂ, which has all the structure we can show applies to it, and this all comes "for free". Should we come up with some new structure in the future that we wish ℂ to inherit, then we change the definition of ℂfld, reprove all the slot extraction theorems, add a new one, and that's it. None of the other downstream theorems have to change. Note that the construct of df-prds 16461 addresses a different situation. It is not possible to have SubGroup and SubRing be the same thing because they produce different outputs on the same input. The subgroups of an extensible structure treated as a group are not the same as the subrings of that same structure. With df-prds 16461 it can actually reasonably perform the task, that is, being the product group given a family of groups, while also being the product ring given a family of rings. There is no contradiction here because the group part of a product ring is a product group. There is also a general theory of "substructure algebras", in the form of df-mre 16599 and df-acs 16602. SubGroup is a Moore collection, as is SubRing, SubRng and many other substructure collections. But it is not useful for picking out a particular collection of interest; SubRing and SubGroup still need to be defined and they are distinct --- nothing is going to select these definitions for us. Extensible structures only work well when they represent concrete categories, where there is a "base set", morphisms are functions, and subobjects are subsets with induced operations. In short, they primarily work well for "sets with (some) extra structure". Extensible structures may not suffice for more complicated situations. For example, in manifolds, ↾s would not work. That said, extensible structures are sufficient for many of the structures that set.mm currently considers, and offer a good compromise for a goal-oriented formalization. | ||
Syntax | cstr 16218 | Extend class notation with the class of structures with components numbered below 𝐴. |
class Struct | ||
Syntax | cnx 16219 | Extend class notation with the structure component index extractor. |
class ndx | ||
Syntax | csts 16220 | Set components of a structure. |
class sSet | ||
Syntax | cslot 16221 | Extend class notation with the slot function. |
class Slot 𝐴 | ||
Syntax | cbs 16222 | Extend class notation with the class of all base set extractors. |
class Base | ||
Syntax | cress 16223 | Extend class notation with the extensible structure builder restriction operator. |
class ↾s | ||
Definition | df-struct 16224* |
Define a structure with components in 𝑀...𝑁. This is not a
requirement for groups, posets, etc., but it is a useful assumption for
component extraction theorems.
As mentioned in the section header, an "extensible structure should be implemented as a function (a set of ordered pairs)". The current definition, however, is less restrictive: it allows for classes which contain the empty set ∅ to be extensible structures. Because of 0nelfun 6141, such classes cannot be functions. Without the empty set, however, a structure must be a function, see structn0fun 16234: 𝐹 Struct 𝑋 → Fun (𝐹 ∖ {∅}). Allowing an extensible structure to contain the empty set ensures that expressions like {〈𝐴, 𝐵〉, 〈𝐶, 𝐷〉} are structures without asserting or implying that 𝐴, 𝐵, 𝐶 and 𝐷 are sets (if 𝐴 or 𝐵 is a proper class, then 〈𝐴, 𝐵〉 = ∅, see opprc 4646). This is used critically in strle1 16332, strle2 16333, strle3 16334 and strleun 16331 to avoid sethood hypotheses on the "payload" sets: without this, ipsstr 16383 and theorems like it will have many sethood assumptions, and may not even be usable in the empty context. Instead, the sethood assumption is deferred until it is actually needed, e.g., ipsbase 16384, which requires that the base set be a set but not any of the other components. Usually, a concrete structure like ℂfld does not contain the empty set, and therefore is a function, see cnfldfun 20118. (Contributed by Mario Carneiro, 29-Aug-2015.) |
⊢ Struct = {〈𝑓, 𝑥〉 ∣ (𝑥 ∈ ( ≤ ∩ (ℕ × ℕ)) ∧ Fun (𝑓 ∖ {∅}) ∧ dom 𝑓 ⊆ (...‘𝑥))} | ||
Definition | df-ndx 16225 | Define the structure component index extractor. See theorem ndxarg 16247 to understand its purpose. The restriction to ℕ ensures that ndx is a set. The restriction to some set is necessary since I is a proper class. In principle, we could have chosen ℂ or (if we revise all structure component definitions such as df-base 16228) another set such as the set of finite ordinals ω (df-om 7327). (Contributed by NM, 4-Sep-2011.) |
⊢ ndx = ( I ↾ ℕ) | ||
Definition | df-slot 16226* |
Define the slot extractor for extensible structures. The class
Slot 𝐴 is a function whose argument can be
any set, although it is
meaningful only if that set is a member of an extensible structure (such
as a partially ordered set (df-poset 17299) or a group (df-grp 17779)).
Note that Slot 𝐴 is implemented as "evaluation at 𝐴". That is, (Slot 𝐴‘𝑆) is defined to be (𝑆‘𝐴), where 𝐴 will typically be a small nonzero natural number. Each extensible structure 𝑆 is a function defined on specific natural number "slots", and this function extracts the value at a particular slot. The special "structure" ndx, defined as the identity function restricted to ℕ, can be used to extract the number 𝐴 from a slot, since (Slot 𝐴‘ndx) = 𝐴 (see ndxarg 16247). This is typically used to refer to the number of a slot when defining structures without having to expose the detail of what that number is (for instance, we use the expression (Base‘ndx) in theorems and proofs instead of its value 1). The class Slot cannot be defined as (𝑥 ∈ V ↦ (𝑓 ∈ V ↦ (𝑓‘𝑥))) because each Slot 𝐴 is a function on the proper class V so is itself a proper class, and the values of functions are sets (fvex 6446). It is necessary to allow proper classes as values of Slot 𝐴 since for instance the class of all (base sets of) groups is proper. (Contributed by Mario Carneiro, 22-Sep-2015.) |
⊢ Slot 𝐴 = (𝑥 ∈ V ↦ (𝑥‘𝐴)) | ||
Theorem | sloteq 16227 | Equality theorem for the Slot construction. The converse holds if 𝐴 (or 𝐵) is a set. (Contributed by BJ, 27-Dec-2021.) |
⊢ (𝐴 = 𝐵 → Slot 𝐴 = Slot 𝐵) | ||
Definition | df-base 16228 | Define the base set (also called underlying set, ground set, carrier set, or carrier) extractor for extensible structures. (Contributed by NM, 4-Sep-2011.) (Revised by Mario Carneiro, 14-Aug-2015.) |
⊢ Base = Slot 1 | ||
Definition | df-sets 16229* | Set a component of an extensible structure. This function is useful for taking an existing structure and "overriding" one of its components. For example, df-ress 16230 adjusts the base set to match its second argument, which has the effect of making subgroups, subspaces, subrings etc. from the original structures. Or df-mgp 18844, which takes a ring and overrides its addition operation with the multiplicative operation, so that we can consider the "multiplicative group" using group and monoid theorems, which expect the operation to be in the +g slot instead of the .r slot. (Contributed by Mario Carneiro, 1-Dec-2014.) |
⊢ sSet = (𝑠 ∈ V, 𝑒 ∈ V ↦ ((𝑠 ↾ (V ∖ dom {𝑒})) ∪ {𝑒})) | ||
Definition | df-ress 16230* |
Define a multifunction restriction operator for extensible structures,
which can be used to turn statements about rings into statements about
subrings, modules into submodules, etc. This definition knows nothing
about individual structures and merely truncates the Base set while
leaving operators alone; individual kinds of structures will need to
handle this behavior, by ignoring operators' values outside the range
(like Ring), defining a function using the base
set and applying
that (like TopGrp), or explicitly truncating the
slot before use
(like MetSp).
(Credit for this operator goes to Mario Carneiro.) See ressbas 16293 for the altered base set, and resslem 16296 (subrg0 19143, ressplusg 16352, subrg1 19146, ressmulr 16365) for the (un)altered other operations. (Contributed by Stefan O'Rear, 29-Nov-2014.) |
⊢ ↾s = (𝑤 ∈ V, 𝑥 ∈ V ↦ if((Base‘𝑤) ⊆ 𝑥, 𝑤, (𝑤 sSet 〈(Base‘ndx), (𝑥 ∩ (Base‘𝑤))〉))) | ||
Theorem | brstruct 16231 | The structure relation is a relation. (Contributed by Mario Carneiro, 29-Aug-2015.) |
⊢ Rel Struct | ||
Theorem | isstruct2 16232 | The property of being a structure with components in (1st ‘𝑋)...(2nd ‘𝑋). (Contributed by Mario Carneiro, 29-Aug-2015.) |
⊢ (𝐹 Struct 𝑋 ↔ (𝑋 ∈ ( ≤ ∩ (ℕ × ℕ)) ∧ Fun (𝐹 ∖ {∅}) ∧ dom 𝐹 ⊆ (...‘𝑋))) | ||
Theorem | structex 16233 | A structure is a set. (Contributed by AV, 10-Nov-2021.) |
⊢ (𝐺 Struct 𝑋 → 𝐺 ∈ V) | ||
Theorem | structn0fun 16234 | A structure without the empty set is a function. (Contributed by AV, 13-Nov-2021.) |
⊢ (𝐹 Struct 𝑋 → Fun (𝐹 ∖ {∅})) | ||
Theorem | isstruct 16235 | The property of being a structure with components in 𝑀...𝑁. (Contributed by Mario Carneiro, 29-Aug-2015.) |
⊢ (𝐹 Struct 〈𝑀, 𝑁〉 ↔ ((𝑀 ∈ ℕ ∧ 𝑁 ∈ ℕ ∧ 𝑀 ≤ 𝑁) ∧ Fun (𝐹 ∖ {∅}) ∧ dom 𝐹 ⊆ (𝑀...𝑁))) | ||
Theorem | structcnvcnv 16236 | Two ways to express the relational part of a structure. (Contributed by Mario Carneiro, 29-Aug-2015.) |
⊢ (𝐹 Struct 𝑋 → ◡◡𝐹 = (𝐹 ∖ {∅})) | ||
Theorem | structfung 16237 | The converse of the converse of a structure is a function. Closed form of structfun 16238. (Contributed by AV, 12-Nov-2021.) |
⊢ (𝐹 Struct 𝑋 → Fun ◡◡𝐹) | ||
Theorem | structfun 16238 | Convert between two kinds of structure closure. (Contributed by Mario Carneiro, 29-Aug-2015.) (Proof shortened by AV, 12-Nov-2021.) |
⊢ 𝐹 Struct 𝑋 ⇒ ⊢ Fun ◡◡𝐹 | ||
Theorem | structfn 16239 | Convert between two kinds of structure closure. (Contributed by Mario Carneiro, 29-Aug-2015.) |
⊢ 𝐹 Struct 〈𝑀, 𝑁〉 ⇒ ⊢ (Fun ◡◡𝐹 ∧ dom 𝐹 ⊆ (1...𝑁)) | ||
Theorem | slotfn 16240 | A slot is a function on sets, treated as structures. (Contributed by Mario Carneiro, 22-Sep-2015.) |
⊢ 𝐸 = Slot 𝑁 ⇒ ⊢ 𝐸 Fn V | ||
Theorem | strfvnd 16241 | Deduction version of strfvn 16244. (Contributed by Mario Carneiro, 15-Nov-2014.) |
⊢ 𝐸 = Slot 𝑁 & ⊢ (𝜑 → 𝑆 ∈ 𝑉) ⇒ ⊢ (𝜑 → (𝐸‘𝑆) = (𝑆‘𝑁)) | ||
Theorem | basfn 16242 | The base set extractor is a function on V. (Contributed by Stefan O'Rear, 8-Jul-2015.) |
⊢ Base Fn V | ||
Theorem | wunndx 16243 | Closure of the index extractor in an infinite weak universe. (Contributed by Mario Carneiro, 12-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → ω ∈ 𝑈) ⇒ ⊢ (𝜑 → ndx ∈ 𝑈) | ||
Theorem | strfvn 16244 |
Value of a structure component extractor 𝐸. Normally, 𝐸 is a
defined constant symbol such as Base (df-base 16228) and 𝑁 is a
fixed integer such as 1. 𝑆 is a structure, i.e. a
specific
member of a class of structures such as Poset
(df-poset 17299) where
𝑆
∈ Poset.
Note: Normally, this theorem shouldn't be used outside of this section, because it requires hard-coded index values. Instead, use strfv 16270. (Contributed by NM, 9-Sep-2011.) (Revised by Mario Carneiro, 6-Oct-2013.) (New usage is discouraged.) |
⊢ 𝑆 ∈ V & ⊢ 𝐸 = Slot 𝑁 ⇒ ⊢ (𝐸‘𝑆) = (𝑆‘𝑁) | ||
Theorem | strfvss 16245 | A structure component extractor produces a value which is contained in a set dependent on 𝑆, but not 𝐸. This is sometimes useful for showing sethood. (Contributed by Mario Carneiro, 15-Aug-2015.) |
⊢ 𝐸 = Slot 𝑁 ⇒ ⊢ (𝐸‘𝑆) ⊆ ∪ ran 𝑆 | ||
Theorem | wunstr 16246 | Closure of a structure index in a weak universe. (Contributed by Mario Carneiro, 12-Jan-2017.) |
⊢ 𝐸 = Slot 𝑁 & ⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝑆 ∈ 𝑈) ⇒ ⊢ (𝜑 → (𝐸‘𝑆) ∈ 𝑈) | ||
Theorem | ndxarg 16247 | Get the numeric argument from a defined structure component extractor such as df-base 16228. (Contributed by Mario Carneiro, 6-Oct-2013.) |
⊢ 𝐸 = Slot 𝑁 & ⊢ 𝑁 ∈ ℕ ⇒ ⊢ (𝐸‘ndx) = 𝑁 | ||
Theorem | ndxid 16248 |
A structure component extractor is defined by its own index. This
theorem, together with strfv 16270 below, is useful for avoiding direct
reference to the hard-coded numeric index in component extractor
definitions, such as the 1 in df-base 16228 and the ;10 in
df-ple 16325, making it easier to change should the need
arise.
For example, we can refer to a specific poset with base set 𝐵 and order relation 𝐿 using {〈(Base‘ndx), 𝐵〉, 〈(le‘ndx), 𝐿〉} rather than {〈1, 𝐵〉, 〈;10, 𝐿〉}. The latter, while shorter to state, requires revision if we later change ;10 to some other number, and it may also be harder to remember. (Contributed by NM, 19-Oct-2012.) (Revised by Mario Carneiro, 6-Oct-2013.) (Proof shortened by BJ, 27-Dec-2021.) |
⊢ 𝐸 = Slot 𝑁 & ⊢ 𝑁 ∈ ℕ ⇒ ⊢ 𝐸 = Slot (𝐸‘ndx) | ||
Theorem | strndxid 16249 | The value of a structure component extractor is the value of the corresponding slot of the structure. (Contributed by AV, 13-Mar-2020.) |
⊢ (𝜑 → 𝑆 ∈ 𝑉) & ⊢ 𝐸 = Slot 𝑁 & ⊢ 𝑁 ∈ ℕ ⇒ ⊢ (𝜑 → (𝑆‘(𝐸‘ndx)) = (𝐸‘𝑆)) | ||
Theorem | reldmsets 16250 | The structure override operator is a proper operator. (Contributed by Stefan O'Rear, 29-Jan-2015.) |
⊢ Rel dom sSet | ||
Theorem | setsvalg 16251 | Value of the structure replacement function. (Contributed by Mario Carneiro, 30-Apr-2015.) |
⊢ ((𝑆 ∈ 𝑉 ∧ 𝐴 ∈ 𝑊) → (𝑆 sSet 𝐴) = ((𝑆 ↾ (V ∖ dom {𝐴})) ∪ {𝐴})) | ||
Theorem | setsval 16252 | Value of the structure replacement function. (Contributed by Mario Carneiro, 1-Dec-2014.) (Revised by Mario Carneiro, 30-Apr-2015.) |
⊢ ((𝑆 ∈ 𝑉 ∧ 𝐵 ∈ 𝑊) → (𝑆 sSet 〈𝐴, 𝐵〉) = ((𝑆 ↾ (V ∖ {𝐴})) ∪ {〈𝐴, 𝐵〉})) | ||
Theorem | setsidvald 16253 | Value of the structure replacement function, deduction version. (Contributed by AV, 14-Mar-2020.) |
⊢ 𝐸 = Slot 𝑁 & ⊢ 𝑁 ∈ ℕ & ⊢ (𝜑 → 𝑆 ∈ 𝑉) & ⊢ (𝜑 → Fun 𝑆) & ⊢ (𝜑 → (𝐸‘ndx) ∈ dom 𝑆) ⇒ ⊢ (𝜑 → 𝑆 = (𝑆 sSet 〈(𝐸‘ndx), (𝐸‘𝑆)〉)) | ||
Theorem | fvsetsid 16254 | The value of the structure replacement function for its first argument is its second argument. (Contributed by SO, 12-Jul-2018.) |
⊢ ((𝐹 ∈ 𝑉 ∧ 𝑋 ∈ 𝑊 ∧ 𝑌 ∈ 𝑈) → ((𝐹 sSet 〈𝑋, 𝑌〉)‘𝑋) = 𝑌) | ||
Theorem | fsets 16255 | The structure replacement function is a function. (Contributed by SO, 12-Jul-2018.) |
⊢ (((𝐹 ∈ 𝑉 ∧ 𝐹:𝐴⟶𝐵) ∧ 𝑋 ∈ 𝐴 ∧ 𝑌 ∈ 𝐵) → (𝐹 sSet 〈𝑋, 𝑌〉):𝐴⟶𝐵) | ||
Theorem | setsdm 16256 | The domain of a structure with replacement is the domain of the original structure extended by the index of the replacement. (Contributed by AV, 7-Jun-2021.) |
⊢ ((𝐺 ∈ 𝑉 ∧ 𝐸 ∈ 𝑊) → dom (𝐺 sSet 〈𝐼, 𝐸〉) = (dom 𝐺 ∪ {𝐼})) | ||
Theorem | setsfun 16257 | A structure with replacement is a function if the original structure is a function. (Contributed by AV, 7-Jun-2021.) |
⊢ (((𝐺 ∈ 𝑉 ∧ Fun 𝐺) ∧ (𝐼 ∈ 𝑈 ∧ 𝐸 ∈ 𝑊)) → Fun (𝐺 sSet 〈𝐼, 𝐸〉)) | ||
Theorem | setsfun0 16258 | A structure with replacement without the empty set is a function if the original structure without the empty set is a function. This variant of setsfun 16257 is useful for proofs based on isstruct2 16232 which requires Fun (𝐹 ∖ {∅}) for 𝐹 to be an extensible structure. (Contributed by AV, 7-Jun-2021.) |
⊢ (((𝐺 ∈ 𝑉 ∧ Fun (𝐺 ∖ {∅})) ∧ (𝐼 ∈ 𝑈 ∧ 𝐸 ∈ 𝑊)) → Fun ((𝐺 sSet 〈𝐼, 𝐸〉) ∖ {∅})) | ||
Theorem | setsn0fun 16259 | The value of the structure replacement function (without the empty set) is a function if the structure (without the empty set) is a function. (Contributed by AV, 7-Jun-2021.) (Revised by AV, 16-Nov-2021.) |
⊢ (𝜑 → 𝑆 Struct 𝑋) & ⊢ (𝜑 → 𝐼 ∈ 𝑈) & ⊢ (𝜑 → 𝐸 ∈ 𝑊) ⇒ ⊢ (𝜑 → Fun ((𝑆 sSet 〈𝐼, 𝐸〉) ∖ {∅})) | ||
Theorem | setsstruct2 16260 | An extensible structure with a replaced slot is an extensible structure. (Contributed by AV, 14-Nov-2021.) |
⊢ (((𝐺 Struct 𝑋 ∧ 𝐸 ∈ 𝑉 ∧ 𝐼 ∈ ℕ) ∧ 𝑌 = 〈if(𝐼 ≤ (1st ‘𝑋), 𝐼, (1st ‘𝑋)), if(𝐼 ≤ (2nd ‘𝑋), (2nd ‘𝑋), 𝐼)〉) → (𝐺 sSet 〈𝐼, 𝐸〉) Struct 𝑌) | ||
Theorem | setsexstruct2 16261* | An extensible structure with a replaced slot is an extensible structure. (Contributed by AV, 14-Nov-2021.) |
⊢ ((𝐺 Struct 𝑋 ∧ 𝐸 ∈ 𝑉 ∧ 𝐼 ∈ ℕ) → ∃𝑦(𝐺 sSet 〈𝐼, 𝐸〉) Struct 𝑦) | ||
Theorem | setsstruct 16262 | An extensible structure with a replaced slot is an extensible structure. (Contributed by AV, 9-Jun-2021.) (Revised by AV, 14-Nov-2021.) |
⊢ ((𝐸 ∈ 𝑉 ∧ 𝐼 ∈ (ℤ≥‘𝑀) ∧ 𝐺 Struct 〈𝑀, 𝑁〉) → (𝐺 sSet 〈𝐼, 𝐸〉) Struct 〈𝑀, if(𝐼 ≤ 𝑁, 𝑁, 𝐼)〉) | ||
Theorem | wunsets 16263 | Closure of structure replacement in a weak universe. (Contributed by Mario Carneiro, 12-Jan-2017.) |
⊢ (𝜑 → 𝑈 ∈ WUni) & ⊢ (𝜑 → 𝑆 ∈ 𝑈) & ⊢ (𝜑 → 𝐴 ∈ 𝑈) ⇒ ⊢ (𝜑 → (𝑆 sSet 𝐴) ∈ 𝑈) | ||
Theorem | setsres 16264 | The structure replacement function does not affect the value of 𝑆 away from 𝐴. (Contributed by Mario Carneiro, 1-Dec-2014.) (Revised by Mario Carneiro, 30-Apr-2015.) |
⊢ (𝑆 ∈ 𝑉 → ((𝑆 sSet 〈𝐴, 𝐵〉) ↾ (V ∖ {𝐴})) = (𝑆 ↾ (V ∖ {𝐴}))) | ||
Theorem | setsabs 16265 | Replacing the same components twice yields the same as the second setting only. (Contributed by Mario Carneiro, 2-Dec-2014.) |
⊢ ((𝑆 ∈ 𝑉 ∧ 𝐶 ∈ 𝑊) → ((𝑆 sSet 〈𝐴, 𝐵〉) sSet 〈𝐴, 𝐶〉) = (𝑆 sSet 〈𝐴, 𝐶〉)) | ||
Theorem | setscom 16266 | Component-setting is commutative when the x-values are different. (Contributed by Mario Carneiro, 5-Dec-2014.) (Revised by Mario Carneiro, 30-Apr-2015.) |
⊢ 𝐴 ∈ V & ⊢ 𝐵 ∈ V ⇒ ⊢ (((𝑆 ∈ 𝑉 ∧ 𝐴 ≠ 𝐵) ∧ (𝐶 ∈ 𝑊 ∧ 𝐷 ∈ 𝑋)) → ((𝑆 sSet 〈𝐴, 𝐶〉) sSet 〈𝐵, 𝐷〉) = ((𝑆 sSet 〈𝐵, 𝐷〉) sSet 〈𝐴, 𝐶〉)) | ||
Theorem | strfvd 16267 | Deduction version of strfv 16270. (Contributed by Mario Carneiro, 15-Nov-2014.) |
⊢ 𝐸 = Slot (𝐸‘ndx) & ⊢ (𝜑 → 𝑆 ∈ 𝑉) & ⊢ (𝜑 → Fun 𝑆) & ⊢ (𝜑 → 〈(𝐸‘ndx), 𝐶〉 ∈ 𝑆) ⇒ ⊢ (𝜑 → 𝐶 = (𝐸‘𝑆)) | ||
Theorem | strfv2d 16268 | Deduction version of strfv2 16269. (Contributed by Mario Carneiro, 30-Apr-2015.) |
⊢ 𝐸 = Slot (𝐸‘ndx) & ⊢ (𝜑 → 𝑆 ∈ 𝑉) & ⊢ (𝜑 → Fun ◡◡𝑆) & ⊢ (𝜑 → 〈(𝐸‘ndx), 𝐶〉 ∈ 𝑆) & ⊢ (𝜑 → 𝐶 ∈ 𝑊) ⇒ ⊢ (𝜑 → 𝐶 = (𝐸‘𝑆)) | ||
Theorem | strfv2 16269 | A variation on strfv 16270 to avoid asserting that 𝑆 itself is a function, which involves sethood of all the ordered pair components of 𝑆. (Contributed by Mario Carneiro, 30-Apr-2015.) |
⊢ 𝑆 ∈ V & ⊢ Fun ◡◡𝑆 & ⊢ 𝐸 = Slot (𝐸‘ndx) & ⊢ 〈(𝐸‘ndx), 𝐶〉 ∈ 𝑆 ⇒ ⊢ (𝐶 ∈ 𝑉 → 𝐶 = (𝐸‘𝑆)) | ||
Theorem | strfv 16270 | Extract a structure component 𝐶 (such as the base set) from a structure 𝑆 (such as a member of Poset, df-poset 17299) with a component extractor 𝐸 (such as the base set extractor df-base 16228). By virtue of ndxid 16248, this can be done without having to refer to the hard-coded numeric index of 𝐸. (Contributed by Mario Carneiro, 6-Oct-2013.) (Revised by Mario Carneiro, 29-Aug-2015.) |
⊢ 𝑆 Struct 𝑋 & ⊢ 𝐸 = Slot (𝐸‘ndx) & ⊢ {〈(𝐸‘ndx), 𝐶〉} ⊆ 𝑆 ⇒ ⊢ (𝐶 ∈ 𝑉 → 𝐶 = (𝐸‘𝑆)) | ||
Theorem | strfv3 16271 | Variant on strfv 16270 for large structures. (Contributed by Mario Carneiro, 10-Jan-2017.) |
⊢ (𝜑 → 𝑈 = 𝑆) & ⊢ 𝑆 Struct 𝑋 & ⊢ 𝐸 = Slot (𝐸‘ndx) & ⊢ {〈(𝐸‘ndx), 𝐶〉} ⊆ 𝑆 & ⊢ (𝜑 → 𝐶 ∈ 𝑉) & ⊢ 𝐴 = (𝐸‘𝑈) ⇒ ⊢ (𝜑 → 𝐴 = 𝐶) | ||
Theorem | strssd 16272 | Deduction version of strss 16273. (Contributed by Mario Carneiro, 15-Nov-2014.) (Revised by Mario Carneiro, 30-Apr-2015.) |
⊢ 𝐸 = Slot (𝐸‘ndx) & ⊢ (𝜑 → 𝑇 ∈ 𝑉) & ⊢ (𝜑 → Fun 𝑇) & ⊢ (𝜑 → 𝑆 ⊆ 𝑇) & ⊢ (𝜑 → 〈(𝐸‘ndx), 𝐶〉 ∈ 𝑆) ⇒ ⊢ (𝜑 → (𝐸‘𝑇) = (𝐸‘𝑆)) | ||
Theorem | strss 16273 | Propagate component extraction to a structure 𝑇 from a subset structure 𝑆. (Contributed by Mario Carneiro, 11-Oct-2013.) (Revised by Mario Carneiro, 15-Jan-2014.) |
⊢ 𝑇 ∈ V & ⊢ Fun 𝑇 & ⊢ 𝑆 ⊆ 𝑇 & ⊢ 𝐸 = Slot (𝐸‘ndx) & ⊢ 〈(𝐸‘ndx), 𝐶〉 ∈ 𝑆 ⇒ ⊢ (𝐸‘𝑇) = (𝐸‘𝑆) | ||
Theorem | str0 16274 | All components of the empty set are empty sets. (Contributed by Stefan O'Rear, 27-Nov-2014.) (Revised by Mario Carneiro, 7-Dec-2014.) |
⊢ 𝐹 = Slot 𝐼 ⇒ ⊢ ∅ = (𝐹‘∅) | ||
Theorem | base0 16275 | The base set of the empty structure. (Contributed by David A. Wheeler, 7-Jul-2016.) |
⊢ ∅ = (Base‘∅) | ||
Theorem | strfvi 16276 | Structure slot extractors cannot distinguish between proper classes and ∅, so they can be protected using the identity function. (Contributed by Stefan O'Rear, 21-Mar-2015.) |
⊢ 𝐸 = Slot 𝑁 & ⊢ 𝑋 = (𝐸‘𝑆) ⇒ ⊢ 𝑋 = (𝐸‘( I ‘𝑆)) | ||
Theorem | setsid 16277 | Value of the structure replacement function at a replaced index. (Contributed by Mario Carneiro, 1-Dec-2014.) (Revised by Mario Carneiro, 30-Apr-2015.) |
⊢ 𝐸 = Slot (𝐸‘ndx) ⇒ ⊢ ((𝑊 ∈ 𝐴 ∧ 𝐶 ∈ 𝑉) → 𝐶 = (𝐸‘(𝑊 sSet 〈(𝐸‘ndx), 𝐶〉))) | ||
Theorem | setsnid 16278 | Value of the structure replacement function at an untouched index. (Contributed by Mario Carneiro, 1-Dec-2014.) (Revised by Mario Carneiro, 30-Apr-2015.) |
⊢ 𝐸 = Slot (𝐸‘ndx) & ⊢ (𝐸‘ndx) ≠ 𝐷 ⇒ ⊢ (𝐸‘𝑊) = (𝐸‘(𝑊 sSet 〈𝐷, 𝐶〉)) | ||
Theorem | sbcie2s 16279* | A special version of class substitution commonly used for structures. (Contributed by Thierry Arnoux, 14-Mar-2019.) |
⊢ 𝐴 = (𝐸‘𝑊) & ⊢ 𝐵 = (𝐹‘𝑊) & ⊢ ((𝑎 = 𝐴 ∧ 𝑏 = 𝐵) → (𝜑 ↔ 𝜓)) ⇒ ⊢ (𝑤 = 𝑊 → ([(𝐸‘𝑤) / 𝑎][(𝐹‘𝑤) / 𝑏]𝜓 ↔ 𝜑)) | ||
Theorem | sbcie3s 16280* | A special version of class substitution commonly used for structures. (Contributed by Thierry Arnoux, 15-Mar-2019.) |
⊢ 𝐴 = (𝐸‘𝑊) & ⊢ 𝐵 = (𝐹‘𝑊) & ⊢ 𝐶 = (𝐺‘𝑊) & ⊢ ((𝑎 = 𝐴 ∧ 𝑏 = 𝐵 ∧ 𝑐 = 𝐶) → (𝜑 ↔ 𝜓)) ⇒ ⊢ (𝑤 = 𝑊 → ([(𝐸‘𝑤) / 𝑎][(𝐹‘𝑤) / 𝑏][(𝐺‘𝑤) / 𝑐]𝜓 ↔ 𝜑)) | ||
Theorem | baseval 16281 | Value of the base set extractor. (Normally it is preferred to work with (Base‘ndx) rather than the hard-coded 1 in order to make structure theorems portable. This is an example of how to obtain it when needed.) (New usage is discouraged.) (Contributed by NM, 4-Sep-2011.) |
⊢ 𝐾 ∈ V ⇒ ⊢ (Base‘𝐾) = (𝐾‘1) | ||
Theorem | baseid 16282 | Utility theorem: index-independent form of df-base 16228. (Contributed by NM, 20-Oct-2012.) |
⊢ Base = Slot (Base‘ndx) | ||
Theorem | elbasfv 16283 | Utility theorem: reverse closure for any structure defined as a function. (Contributed by Stefan O'Rear, 24-Aug-2015.) |
⊢ 𝑆 = (𝐹‘𝑍) & ⊢ 𝐵 = (Base‘𝑆) ⇒ ⊢ (𝑋 ∈ 𝐵 → 𝑍 ∈ V) | ||
Theorem | elbasov 16284 | Utility theorem: reverse closure for any structure defined as a two-argument function. (Contributed by Mario Carneiro, 3-Oct-2015.) |
⊢ Rel dom 𝑂 & ⊢ 𝑆 = (𝑋𝑂𝑌) & ⊢ 𝐵 = (Base‘𝑆) ⇒ ⊢ (𝐴 ∈ 𝐵 → (𝑋 ∈ V ∧ 𝑌 ∈ V)) | ||
Theorem | strov2rcl 16285 | Partial reverse closure for any structure defined as a two-argument function. (Contributed by Stefan O'Rear, 27-Mar-2015.) (Proof shortened by AV, 2-Dec-2019.) |
⊢ 𝑆 = (𝐼𝐹𝑅) & ⊢ 𝐵 = (Base‘𝑆) & ⊢ Rel dom 𝐹 ⇒ ⊢ (𝑋 ∈ 𝐵 → 𝐼 ∈ V) | ||
Theorem | basendx 16286 | Index value of the base set extractor. (Normally it is preferred to work with (Base‘ndx) rather than the hard-coded 1 in order to make structure theorems portable. This is an example of how to obtain it when needed.) (New usage is discouraged.) (Contributed by Mario Carneiro, 2-Aug-2013.) |
⊢ (Base‘ndx) = 1 | ||
Theorem | basendxnn 16287 | The index value of the base set extractor is a positive integer. This property should be ensured for every concrete coding because otherwise it could not be used in an extensible structure (slots must be positive integers). (Contributed by AV, 23-Sep-2020.) |
⊢ (Base‘ndx) ∈ ℕ | ||
Theorem | basprssdmsets 16288 | The pair of the base index and another index is a subset of the domain of the structure obtained by replacing/adding a slot at the other index in a structure having a base slot. (Contributed by AV, 7-Jun-2021.) (Revised by AV, 16-Nov-2021.) |
⊢ (𝜑 → 𝑆 Struct 𝑋) & ⊢ (𝜑 → 𝐼 ∈ 𝑈) & ⊢ (𝜑 → 𝐸 ∈ 𝑊) & ⊢ (𝜑 → (Base‘ndx) ∈ dom 𝑆) ⇒ ⊢ (𝜑 → {(Base‘ndx), 𝐼} ⊆ dom (𝑆 sSet 〈𝐼, 𝐸〉)) | ||
Theorem | reldmress 16289 | The structure restriction is a proper operator, so it can be used with ovprc1 6943. (Contributed by Stefan O'Rear, 29-Nov-2014.) |
⊢ Rel dom ↾s | ||
Theorem | ressval 16290 | Value of structure restriction. (Contributed by Stefan O'Rear, 29-Nov-2014.) |
⊢ 𝑅 = (𝑊 ↾s 𝐴) & ⊢ 𝐵 = (Base‘𝑊) ⇒ ⊢ ((𝑊 ∈ 𝑋 ∧ 𝐴 ∈ 𝑌) → 𝑅 = if(𝐵 ⊆ 𝐴, 𝑊, (𝑊 sSet 〈(Base‘ndx), (𝐴 ∩ 𝐵)〉))) | ||
Theorem | ressid2 16291 | General behavior of trivial restriction. (Contributed by Stefan O'Rear, 29-Nov-2014.) |
⊢ 𝑅 = (𝑊 ↾s 𝐴) & ⊢ 𝐵 = (Base‘𝑊) ⇒ ⊢ ((𝐵 ⊆ 𝐴 ∧ 𝑊 ∈ 𝑋 ∧ 𝐴 ∈ 𝑌) → 𝑅 = 𝑊) | ||
Theorem | ressval2 16292 | Value of nontrivial structure restriction. (Contributed by Stefan O'Rear, 29-Nov-2014.) |
⊢ 𝑅 = (𝑊 ↾s 𝐴) & ⊢ 𝐵 = (Base‘𝑊) ⇒ ⊢ ((¬ 𝐵 ⊆ 𝐴 ∧ 𝑊 ∈ 𝑋 ∧ 𝐴 ∈ 𝑌) → 𝑅 = (𝑊 sSet 〈(Base‘ndx), (𝐴 ∩ 𝐵)〉)) | ||
Theorem | ressbas 16293 | Base set of a structure restriction. (Contributed by Stefan O'Rear, 26-Nov-2014.) |
⊢ 𝑅 = (𝑊 ↾s 𝐴) & ⊢ 𝐵 = (Base‘𝑊) ⇒ ⊢ (𝐴 ∈ 𝑉 → (𝐴 ∩ 𝐵) = (Base‘𝑅)) | ||
Theorem | ressbas2 16294 | Base set of a structure restriction. (Contributed by Mario Carneiro, 2-Dec-2014.) |
⊢ 𝑅 = (𝑊 ↾s 𝐴) & ⊢ 𝐵 = (Base‘𝑊) ⇒ ⊢ (𝐴 ⊆ 𝐵 → 𝐴 = (Base‘𝑅)) | ||
Theorem | ressbasss 16295 | The base set of a restriction is a subset of the base set of the original structure. (Contributed by Stefan O'Rear, 27-Nov-2014.) (Revised by Mario Carneiro, 30-Apr-2015.) |
⊢ 𝑅 = (𝑊 ↾s 𝐴) & ⊢ 𝐵 = (Base‘𝑊) ⇒ ⊢ (Base‘𝑅) ⊆ 𝐵 | ||
Theorem | resslem 16296 | Other elements of a structure restriction. (Contributed by Mario Carneiro, 26-Nov-2014.) (Revised by Mario Carneiro, 2-Dec-2014.) |
⊢ 𝑅 = (𝑊 ↾s 𝐴) & ⊢ 𝐶 = (𝐸‘𝑊) & ⊢ 𝐸 = Slot 𝑁 & ⊢ 𝑁 ∈ ℕ & ⊢ 1 < 𝑁 ⇒ ⊢ (𝐴 ∈ 𝑉 → 𝐶 = (𝐸‘𝑅)) | ||
Theorem | ress0 16297 | All restrictions of the null set are trivial. (Contributed by Stefan O'Rear, 29-Nov-2014.) (Revised by Mario Carneiro, 30-Apr-2015.) |
⊢ (∅ ↾s 𝐴) = ∅ | ||
Theorem | ressid 16298 | Behavior of trivial restriction. (Contributed by Stefan O'Rear, 29-Nov-2014.) |
⊢ 𝐵 = (Base‘𝑊) ⇒ ⊢ (𝑊 ∈ 𝑋 → (𝑊 ↾s 𝐵) = 𝑊) | ||
Theorem | ressinbas 16299 | Restriction only cares about the part of the second set which intersects the base of the first. (Contributed by Stefan O'Rear, 29-Nov-2014.) |
⊢ 𝐵 = (Base‘𝑊) ⇒ ⊢ (𝐴 ∈ 𝑋 → (𝑊 ↾s 𝐴) = (𝑊 ↾s (𝐴 ∩ 𝐵))) | ||
Theorem | ressval3d 16300 | Value of structure restriction, deduction version. (Contributed by AV, 14-Mar-2020.) (Revised by AV, 3-Jul-2022.) |
⊢ 𝑅 = (𝑆 ↾s 𝐴) & ⊢ 𝐵 = (Base‘𝑆) & ⊢ 𝐸 = (Base‘ndx) & ⊢ (𝜑 → 𝑆 ∈ 𝑉) & ⊢ (𝜑 → Fun 𝑆) & ⊢ (𝜑 → 𝐸 ∈ dom 𝑆) & ⊢ (𝜑 → 𝐴 ⊆ 𝐵) ⇒ ⊢ (𝜑 → 𝑅 = (𝑆 sSet 〈𝐸, 𝐴〉)) |
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