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Theorem List for Metamath Proof Explorer - 37301-37400   *Has distinct variable group(s)
TypeLabelDescription
Statement

Theoremntrneik2 37301* An interior function is contracting if and only if all the neighborhoods of a point contain that point. (Contributed by RP, 11-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   (𝜑𝐼𝐹𝑁)       (𝜑 → (∀𝑠 ∈ 𝒫 𝐵(𝐼𝑠) ⊆ 𝑠 ↔ ∀𝑥𝐵𝑠 ∈ 𝒫 𝐵(𝑠 ∈ (𝑁𝑥) → 𝑥𝑠)))

Theoremntrneix2 37302* An interior (closure) function is expansive if and only if all subsets which contain a point are neighborhoods (convergents) of that point. (Contributed by RP, 11-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   (𝜑𝐼𝐹𝑁)       (𝜑 → (∀𝑠 ∈ 𝒫 𝐵𝑠 ⊆ (𝐼𝑠) ↔ ∀𝑥𝐵𝑠 ∈ 𝒫 𝐵(𝑥𝑠𝑠 ∈ (𝑁𝑥))))

Theoremntrneikb 37303* The interiors of disjoint sets are disjoint if and only if the neighborhoods of every point contain no disjoint sets. (Contributed by RP, 11-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   (𝜑𝐼𝐹𝑁)       (𝜑 → (∀𝑠 ∈ 𝒫 𝐵𝑡 ∈ 𝒫 𝐵((𝑠𝑡) = ∅ → ((𝐼𝑠) ∩ (𝐼𝑡)) = ∅) ↔ ∀𝑥𝐵𝑠 ∈ 𝒫 𝐵𝑡 ∈ 𝒫 𝐵((𝑠 ∈ (𝑁𝑥) ∧ 𝑡 ∈ (𝑁𝑥)) → (𝑠𝑡) ≠ ∅)))

Theoremntrneixb 37304* The interiors (closures) of sets that span the base set also span the base set if and only if the neighborhoods (convergents) of every point contain at least one of every pair of sets that span the base set. (Contributed by RP, 11-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   (𝜑𝐼𝐹𝑁)       (𝜑 → (∀𝑠 ∈ 𝒫 𝐵𝑡 ∈ 𝒫 𝐵((𝑠𝑡) = 𝐵 → ((𝐼𝑠) ∪ (𝐼𝑡)) = 𝐵) ↔ ∀𝑥𝐵𝑠 ∈ 𝒫 𝐵𝑡 ∈ 𝒫 𝐵((𝑠𝑡) = 𝐵 → (𝑠 ∈ (𝑁𝑥) ∨ 𝑡 ∈ (𝑁𝑥)))))

Theoremntrneik3 37305* The intersection of interiors of any pair is a subset of the interior of the intersection if and only if the intersection of any two neighborhoods of a point is also a neighborhood. (Contributed by RP, 19-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   (𝜑𝐼𝐹𝑁)       (𝜑 → (∀𝑠 ∈ 𝒫 𝐵𝑡 ∈ 𝒫 𝐵((𝐼𝑠) ∩ (𝐼𝑡)) ⊆ (𝐼‘(𝑠𝑡)) ↔ ∀𝑥𝐵𝑠 ∈ 𝒫 𝐵𝑡 ∈ 𝒫 𝐵((𝑠 ∈ (𝑁𝑥) ∧ 𝑡 ∈ (𝑁𝑥)) → (𝑠𝑡) ∈ (𝑁𝑥))))

Theoremntrneix3 37306* The closure of the union of any pair is a subset of the union of closures if and only if the union of any pair belonging to the convergents of a point implies at least one of the pair belongs to the the convergents of that point. (Contributed by RP, 19-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   (𝜑𝐼𝐹𝑁)       (𝜑 → (∀𝑠 ∈ 𝒫 𝐵𝑡 ∈ 𝒫 𝐵(𝐼‘(𝑠𝑡)) ⊆ ((𝐼𝑠) ∪ (𝐼𝑡)) ↔ ∀𝑥𝐵𝑠 ∈ 𝒫 𝐵𝑡 ∈ 𝒫 𝐵((𝑠𝑡) ∈ (𝑁𝑥) → (𝑠 ∈ (𝑁𝑥) ∨ 𝑡 ∈ (𝑁𝑥)))))

Theoremntrneik13 37307* The interior of the intersection of any pair equals intersection of interiors if and only if the intersection of any pair belonging to the neighborhood of a point is equivalent to both of the pair belonging to the neighborhood of that point. (Contributed by RP, 19-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   (𝜑𝐼𝐹𝑁)       (𝜑 → (∀𝑠 ∈ 𝒫 𝐵𝑡 ∈ 𝒫 𝐵(𝐼‘(𝑠𝑡)) = ((𝐼𝑠) ∩ (𝐼𝑡)) ↔ ∀𝑥𝐵𝑠 ∈ 𝒫 𝐵𝑡 ∈ 𝒫 𝐵((𝑠𝑡) ∈ (𝑁𝑥) ↔ (𝑠 ∈ (𝑁𝑥) ∧ 𝑡 ∈ (𝑁𝑥)))))

Theoremntrneix13 37308* The closure of the union of any pair is equal to the union of closures if and only if the union of any pair belonging to the convergents of a point if equivalent to at least one of the pain belonging to the convergents of that point. (Contributed by RP, 19-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   (𝜑𝐼𝐹𝑁)       (𝜑 → (∀𝑠 ∈ 𝒫 𝐵𝑡 ∈ 𝒫 𝐵(𝐼‘(𝑠𝑡)) = ((𝐼𝑠) ∪ (𝐼𝑡)) ↔ ∀𝑥𝐵𝑠 ∈ 𝒫 𝐵𝑡 ∈ 𝒫 𝐵((𝑠𝑡) ∈ (𝑁𝑥) ↔ (𝑠 ∈ (𝑁𝑥) ∨ 𝑡 ∈ (𝑁𝑥)))))

Theoremntrneik4w 37309* Idempotence of the interior function is equivalent to saying a set is a neighborhood of a point if and only if the interior of the set is a neighborhood of a point. (Contributed by RP, 11-Jul-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   (𝜑𝐼𝐹𝑁)       (𝜑 → (∀𝑠 ∈ 𝒫 𝐵(𝐼‘(𝐼𝑠)) = (𝐼𝑠) ↔ ∀𝑥𝐵𝑠 ∈ 𝒫 𝐵(𝑠 ∈ (𝑁𝑥) ↔ (𝐼𝑠) ∈ (𝑁𝑥))))

Theoremntrneik4 37310* Idempotence of the interior function is equivalent to stating a set, 𝑠, is a neighborhood of a point, 𝑥 is equivalent to there existing a special neighborhood, 𝑢, of 𝑥 such that a point is an element of the special neighborhood if and only if 𝑠 is also a neighborhood of the point. (Contributed by RP, 11-Jul-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   (𝜑𝐼𝐹𝑁)       (𝜑 → (∀𝑠 ∈ 𝒫 𝐵(𝐼‘(𝐼𝑠)) = (𝐼𝑠) ↔ ∀𝑥𝐵𝑠 ∈ 𝒫 𝐵(𝑠 ∈ (𝑁𝑥) ↔ ∃𝑢 ∈ (𝑁𝑥)∀𝑦𝐵 (𝑦𝑢𝑠 ∈ (𝑁𝑦)))))

Theoremclsneibex 37311 If (pseudo-)closure and (pseudo-)neighborhood functions are related by the composite operator, 𝐻, then the base set exists. (Contributed by RP, 4-Jun-2021.)
𝐷 = (𝑃𝐵)    &   𝐻 = (𝐹𝐷)    &   (𝜑𝐾𝐻𝑁)       (𝜑𝐵 ∈ V)

Theoremclsneircomplex 37312 The relative complement of the class 𝑆 exists as a subset of the base set. (Contributed by RP, 26-Jun-2021.)
𝐷 = (𝑃𝐵)    &   𝐻 = (𝐹𝐷)    &   (𝜑𝐾𝐻𝑁)       (𝜑 → (𝐵𝑆) ∈ 𝒫 𝐵)

Theoremclsneif1o 37313* If a (pseudo-)closure function and a (pseudo-)neighborhood function are related by the 𝐻 operator, then the operator is a one-to-one, onto mapping. (Contributed by RP, 5-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝑃 = (𝑛 ∈ V ↦ (𝑝 ∈ (𝒫 𝑛𝑚 𝒫 𝑛) ↦ (𝑜 ∈ 𝒫 𝑛 ↦ (𝑛 ∖ (𝑝‘(𝑛𝑜))))))    &   𝐷 = (𝑃𝐵)    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   𝐻 = (𝐹𝐷)    &   (𝜑𝐾𝐻𝑁)       (𝜑𝐻:(𝒫 𝐵𝑚 𝒫 𝐵)–1-1-onto→(𝒫 𝒫 𝐵𝑚 𝐵))

Theoremclsneicnv 37314* If a (pseudo-)closure function and a (pseudo-)neighborhood function are related by the 𝐻 operator, then the converse of the operator is known. (Contributed by RP, 5-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝑃 = (𝑛 ∈ V ↦ (𝑝 ∈ (𝒫 𝑛𝑚 𝒫 𝑛) ↦ (𝑜 ∈ 𝒫 𝑛 ↦ (𝑛 ∖ (𝑝‘(𝑛𝑜))))))    &   𝐷 = (𝑃𝐵)    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   𝐻 = (𝐹𝐷)    &   (𝜑𝐾𝐻𝑁)       (𝜑𝐻 = (𝐷 ∘ (𝐵𝑂𝒫 𝐵)))

Theoremclsneikex 37315* If closure and neighborhoods functions are related, the closure function exists. (Contributed by RP, 27-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝑃 = (𝑛 ∈ V ↦ (𝑝 ∈ (𝒫 𝑛𝑚 𝒫 𝑛) ↦ (𝑜 ∈ 𝒫 𝑛 ↦ (𝑛 ∖ (𝑝‘(𝑛𝑜))))))    &   𝐷 = (𝑃𝐵)    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   𝐻 = (𝐹𝐷)    &   (𝜑𝐾𝐻𝑁)       (𝜑𝐾 ∈ (𝒫 𝐵𝑚 𝒫 𝐵))

Theoremclsneinex 37316* If closure and neighborhoods functions are related, the neighborhoods function exists. (Contributed by RP, 27-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝑃 = (𝑛 ∈ V ↦ (𝑝 ∈ (𝒫 𝑛𝑚 𝒫 𝑛) ↦ (𝑜 ∈ 𝒫 𝑛 ↦ (𝑛 ∖ (𝑝‘(𝑛𝑜))))))    &   𝐷 = (𝑃𝐵)    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   𝐻 = (𝐹𝐷)    &   (𝜑𝐾𝐻𝑁)       (𝜑𝑁 ∈ (𝒫 𝒫 𝐵𝑚 𝐵))

Theoremclsneiel1 37317* If a (pseudo-)closure function and a (pseudo-)neighborhood function are related by the 𝐻 operator, then membership in the closure of a subset is equivalent to the complement of the subset not being a neighborhood of the point. (Contributed by RP, 7-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝑃 = (𝑛 ∈ V ↦ (𝑝 ∈ (𝒫 𝑛𝑚 𝒫 𝑛) ↦ (𝑜 ∈ 𝒫 𝑛 ↦ (𝑛 ∖ (𝑝‘(𝑛𝑜))))))    &   𝐷 = (𝑃𝐵)    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   𝐻 = (𝐹𝐷)    &   (𝜑𝐾𝐻𝑁)    &   (𝜑𝑋𝐵)    &   (𝜑𝑆 ∈ 𝒫 𝐵)       (𝜑 → (𝑋 ∈ (𝐾𝑆) ↔ ¬ (𝐵𝑆) ∈ (𝑁𝑋)))

Theoremclsneiel2 37318* If a (pseudo-)closure function and a (pseudo-)neighborhood function are related by the 𝐻 operator, then membership in the closure of the complement of a subset is equivalent to the subset not being a neighborhood of the point. (Contributed by RP, 7-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝑃 = (𝑛 ∈ V ↦ (𝑝 ∈ (𝒫 𝑛𝑚 𝒫 𝑛) ↦ (𝑜 ∈ 𝒫 𝑛 ↦ (𝑛 ∖ (𝑝‘(𝑛𝑜))))))    &   𝐷 = (𝑃𝐵)    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   𝐻 = (𝐹𝐷)    &   (𝜑𝐾𝐻𝑁)    &   (𝜑𝑋𝐵)    &   (𝜑𝑆 ∈ 𝒫 𝐵)       (𝜑 → (𝑋 ∈ (𝐾‘(𝐵𝑆)) ↔ ¬ 𝑆 ∈ (𝑁𝑋)))

Theoremclsneifv3 37319* Value of the neighborhoods (convergents) in terms of the closure (interior) function. (Contributed by RP, 27-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝑃 = (𝑛 ∈ V ↦ (𝑝 ∈ (𝒫 𝑛𝑚 𝒫 𝑛) ↦ (𝑜 ∈ 𝒫 𝑛 ↦ (𝑛 ∖ (𝑝‘(𝑛𝑜))))))    &   𝐷 = (𝑃𝐵)    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   𝐻 = (𝐹𝐷)    &   (𝜑𝐾𝐻𝑁)    &   (𝜑𝑋𝐵)       (𝜑 → (𝑁𝑋) = {𝑠 ∈ 𝒫 𝐵 ∣ ¬ 𝑋 ∈ (𝐾‘(𝐵𝑠))})

Theoremclsneifv4 37320* Value of the the closure (interior) function in terms of the neighborhoods (convergents) function. (Contributed by RP, 27-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝑃 = (𝑛 ∈ V ↦ (𝑝 ∈ (𝒫 𝑛𝑚 𝒫 𝑛) ↦ (𝑜 ∈ 𝒫 𝑛 ↦ (𝑛 ∖ (𝑝‘(𝑛𝑜))))))    &   𝐷 = (𝑃𝐵)    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   𝐻 = (𝐹𝐷)    &   (𝜑𝐾𝐻𝑁)    &   (𝜑𝑆 ∈ 𝒫 𝐵)       (𝜑 → (𝐾𝑆) = {𝑥𝐵 ∣ ¬ (𝐵𝑆) ∈ (𝑁𝑥)})

Theoremneicvgbex 37321 If (pseudo-)neighborhood and (pseudo-)convergent functions are related by the composite operator, 𝐻, then the base set exists. (Contributed by RP, 4-Jun-2021.)
𝐷 = (𝑃𝐵)    &   𝐻 = (𝐹 ∘ (𝐷𝐺))    &   (𝜑𝑁𝐻𝑀)       (𝜑𝐵 ∈ V)

Theoremneicvgrcomplex 37322 The relative complement of the class 𝑆 exists as a subset of the base set. (Contributed by RP, 26-Jun-2021.)
𝐷 = (𝑃𝐵)    &   𝐻 = (𝐹 ∘ (𝐷𝐺))    &   (𝜑𝑁𝐻𝑀)       (𝜑 → (𝐵𝑆) ∈ 𝒫 𝐵)

Theoremneicvgf1o 37323* If neighborhood and convergent functions are related by operator 𝐻, it is a one-to-one onto relation. (Contributed by RP, 11-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝑃 = (𝑛 ∈ V ↦ (𝑝 ∈ (𝒫 𝑛𝑚 𝒫 𝑛) ↦ (𝑜 ∈ 𝒫 𝑛 ↦ (𝑛 ∖ (𝑝‘(𝑛𝑜))))))    &   𝐷 = (𝑃𝐵)    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   𝐺 = (𝐵𝑂𝒫 𝐵)    &   𝐻 = (𝐹 ∘ (𝐷𝐺))    &   (𝜑𝑁𝐻𝑀)       (𝜑𝐻:(𝒫 𝒫 𝐵𝑚 𝐵)–1-1-onto→(𝒫 𝒫 𝐵𝑚 𝐵))

Theoremneicvgnvo 37324* If neighborhood and convergent functions are related by operator 𝐻, it is its own converse function. (Contributed by RP, 11-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝑃 = (𝑛 ∈ V ↦ (𝑝 ∈ (𝒫 𝑛𝑚 𝒫 𝑛) ↦ (𝑜 ∈ 𝒫 𝑛 ↦ (𝑛 ∖ (𝑝‘(𝑛𝑜))))))    &   𝐷 = (𝑃𝐵)    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   𝐺 = (𝐵𝑂𝒫 𝐵)    &   𝐻 = (𝐹 ∘ (𝐷𝐺))    &   (𝜑𝑁𝐻𝑀)       (𝜑𝐻 = 𝐻)

Theoremneicvgnvor 37325* If neighborhood and convergent functions are related by operator 𝐻, the relationship holds with the functions swapped. (Contributed by RP, 11-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝑃 = (𝑛 ∈ V ↦ (𝑝 ∈ (𝒫 𝑛𝑚 𝒫 𝑛) ↦ (𝑜 ∈ 𝒫 𝑛 ↦ (𝑛 ∖ (𝑝‘(𝑛𝑜))))))    &   𝐷 = (𝑃𝐵)    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   𝐺 = (𝐵𝑂𝒫 𝐵)    &   𝐻 = (𝐹 ∘ (𝐷𝐺))    &   (𝜑𝑁𝐻𝑀)       (𝜑𝑀𝐻𝑁)

Theoremneicvgmex 37326* If the neighborhoods and convergents functions are related, the convergents function exists. (Contributed by RP, 27-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝑃 = (𝑛 ∈ V ↦ (𝑝 ∈ (𝒫 𝑛𝑚 𝒫 𝑛) ↦ (𝑜 ∈ 𝒫 𝑛 ↦ (𝑛 ∖ (𝑝‘(𝑛𝑜))))))    &   𝐷 = (𝑃𝐵)    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   𝐺 = (𝐵𝑂𝒫 𝐵)    &   𝐻 = (𝐹 ∘ (𝐷𝐺))    &   (𝜑𝑁𝐻𝑀)       (𝜑𝑀 ∈ (𝒫 𝒫 𝐵𝑚 𝐵))

Theoremneicvgnex 37327* If the neighborhoods and convergents functions are related, the neighborhoods function exists. (Contributed by RP, 27-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝑃 = (𝑛 ∈ V ↦ (𝑝 ∈ (𝒫 𝑛𝑚 𝒫 𝑛) ↦ (𝑜 ∈ 𝒫 𝑛 ↦ (𝑛 ∖ (𝑝‘(𝑛𝑜))))))    &   𝐷 = (𝑃𝐵)    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   𝐺 = (𝐵𝑂𝒫 𝐵)    &   𝐻 = (𝐹 ∘ (𝐷𝐺))    &   (𝜑𝑁𝐻𝑀)       (𝜑𝑁 ∈ (𝒫 𝒫 𝐵𝑚 𝐵))

Theoremneicvgel1 37328* A subset being an element of a neighborhood of a point is equivalent to the complement of that subset not being a element of the convergent of that point. (Contributed by RP, 12-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝑃 = (𝑛 ∈ V ↦ (𝑝 ∈ (𝒫 𝑛𝑚 𝒫 𝑛) ↦ (𝑜 ∈ 𝒫 𝑛 ↦ (𝑛 ∖ (𝑝‘(𝑛𝑜))))))    &   𝐷 = (𝑃𝐵)    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   𝐺 = (𝐵𝑂𝒫 𝐵)    &   𝐻 = (𝐹 ∘ (𝐷𝐺))    &   (𝜑𝑁𝐻𝑀)    &   (𝜑𝑋𝐵)    &   (𝜑𝑆 ∈ 𝒫 𝐵)       (𝜑 → (𝑆 ∈ (𝑁𝑋) ↔ ¬ (𝐵𝑆) ∈ (𝑀𝑋)))

Theoremneicvgel2 37329* The complement of a subset being an element of a neighborhood at a point is equivalent to that subset not being a element of the convergent at that point. (Contributed by RP, 12-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝑃 = (𝑛 ∈ V ↦ (𝑝 ∈ (𝒫 𝑛𝑚 𝒫 𝑛) ↦ (𝑜 ∈ 𝒫 𝑛 ↦ (𝑛 ∖ (𝑝‘(𝑛𝑜))))))    &   𝐷 = (𝑃𝐵)    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   𝐺 = (𝐵𝑂𝒫 𝐵)    &   𝐻 = (𝐹 ∘ (𝐷𝐺))    &   (𝜑𝑁𝐻𝑀)    &   (𝜑𝑋𝐵)    &   (𝜑𝑆 ∈ 𝒫 𝐵)       (𝜑 → ((𝐵𝑆) ∈ (𝑁𝑋) ↔ ¬ 𝑆 ∈ (𝑀𝑋)))

Theoremneicvgfv 37330* The value of the neighborhoods (convergents) in terms of the the convergents (neighborhoods) function. (Contributed by RP, 27-Jun-2021.)
𝑂 = (𝑖 ∈ V, 𝑗 ∈ V ↦ (𝑘 ∈ (𝒫 𝑗𝑚 𝑖) ↦ (𝑙𝑗 ↦ {𝑚𝑖𝑙 ∈ (𝑘𝑚)})))    &   𝑃 = (𝑛 ∈ V ↦ (𝑝 ∈ (𝒫 𝑛𝑚 𝒫 𝑛) ↦ (𝑜 ∈ 𝒫 𝑛 ↦ (𝑛 ∖ (𝑝‘(𝑛𝑜))))))    &   𝐷 = (𝑃𝐵)    &   𝐹 = (𝒫 𝐵𝑂𝐵)    &   𝐺 = (𝐵𝑂𝒫 𝐵)    &   𝐻 = (𝐹 ∘ (𝐷𝐺))    &   (𝜑𝑁𝐻𝑀)    &   (𝜑𝑋𝐵)       (𝜑 → (𝑁𝑋) = {𝑠 ∈ 𝒫 𝐵 ∣ ¬ (𝐵𝑠) ∈ (𝑀𝑋)})

Theoremntrrn 37331 The range of the interior function of a topology a subset of the open sets of the topology. (Contributed by RP, 22-Apr-2021.)
𝑋 = 𝐽    &   𝐼 = (int‘𝐽)       (𝐽 ∈ Top → ran 𝐼𝐽)

Theoremntrf 37332 The interior function of a topology is a map from the powerset of the base set to the open sets of the topology. (Contributed by RP, 22-Apr-2021.)
𝑋 = 𝐽    &   𝐼 = (int‘𝐽)       (𝐽 ∈ Top → 𝐼:𝒫 𝑋𝐽)

Theoremntrf2 37333 The interior function is a map from the powerset of the base set to itself. (Contributed by RP, 22-Apr-2021.)
𝑋 = 𝐽    &   𝐼 = (int‘𝐽)       (𝐽 ∈ Top → 𝐼:𝒫 𝑋⟶𝒫 𝑋)

Theoremntrelmap 37334 The interior function is a map from the powerset of the base set to itself. (Contributed by RP, 22-Apr-2021.)
𝑋 = 𝐽    &   𝐼 = (int‘𝐽)       (𝐽 ∈ Top → 𝐼 ∈ (𝒫 𝑋𝑚 𝒫 𝑋))

Theoremclsf2 37335 The closure function is a map from the powerset of the base set to itself. This is less precise than clsf 20568. (Contributed by RP, 22-Apr-2021.)
𝑋 = 𝐽    &   𝐾 = (cls‘𝐽)       (𝐽 ∈ Top → 𝐾:𝒫 𝑋⟶𝒫 𝑋)

Theoremclselmap 37336 The closure function is a map from the powerset of the base set to itself. (Contributed by RP, 22-Apr-2021.)
𝑋 = 𝐽    &   𝐾 = (cls‘𝐽)       (𝐽 ∈ Top → 𝐾 ∈ (𝒫 𝑋𝑚 𝒫 𝑋))

Theoremdssmapntrcls 37337* The interior and closure operators on a topology are duals of each other. See also kur14lem2 30282. (Contributed by RP, 21-Apr-2021.)
𝑋 = 𝐽    &   𝐾 = (cls‘𝐽)    &   𝐼 = (int‘𝐽)    &   𝑂 = (𝑏 ∈ V ↦ (𝑓 ∈ (𝒫 𝑏𝑚 𝒫 𝑏) ↦ (𝑠 ∈ 𝒫 𝑏 ↦ (𝑏 ∖ (𝑓‘(𝑏𝑠))))))    &   𝐷 = (𝑂𝑋)       (𝐽 ∈ Top → 𝐼 = (𝐷𝐾))

Theoremdssmapclsntr 37338* The closure and interior operators on a topology are duals of each other. See also kur14lem2 30282. (Contributed by RP, 22-Apr-2021.)
𝑋 = 𝐽    &   𝐾 = (cls‘𝐽)    &   𝐼 = (int‘𝐽)    &   𝑂 = (𝑏 ∈ V ↦ (𝑓 ∈ (𝒫 𝑏𝑚 𝒫 𝑏) ↦ (𝑠 ∈ 𝒫 𝑏 ↦ (𝑏 ∖ (𝑓‘(𝑏𝑠))))))    &   𝐷 = (𝑂𝑋)       (𝐽 ∈ Top → 𝐾 = (𝐷𝐼))

20.26.4.3  Generic Neighborhood Spaces

Any neighborhood space is an open set topology and any open set topology is a neighborhood space. Seifert And Threlfall define a generic neighborhood space which is a superset of what is now generally used and related concepts and the following will show that those definitions apply to elements of Top.

Seifert And Threlfall do not allow neighborhood spaces on the empty set while sn0top 20519 is an example of a topology with an empty base set. This divergence is unlikely to pose serious problems.

Theoremgneispa 37339* Each point 𝑝 of the neighborhood space has at least one neighborhood; each neighborhood of 𝑝 contains 𝑝. Axiom A of Seifert And Threlfall. (Contributed by RP, 5-Apr-2021.)
𝑋 = 𝐽       (𝐽 ∈ Top → ∀𝑝𝑋 (((nei‘𝐽)‘{𝑝}) ≠ ∅ ∧ ∀𝑛 ∈ ((nei‘𝐽)‘{𝑝})𝑝𝑛))

Theoremgneispb 37340* Given a neighborhood 𝑁 of 𝑃, each subset of the neighborhood space containing this neighborhood is also a neighborhood of 𝑃. Axiom B of Seifert And Threlfall. (Contributed by RP, 5-Apr-2021.)
𝑋 = 𝐽       ((𝐽 ∈ Top ∧ 𝑃𝑋𝑁 ∈ ((nei‘𝐽)‘{𝑃})) → ∀𝑠 ∈ 𝒫 𝑋(𝑁𝑠𝑠 ∈ ((nei‘𝐽)‘{𝑃})))

Theoremgneispace2 37341* The predicate that 𝐹 is a (generic) Seifert And Threlfall neighborhood space. (Contributed by RP, 15-Apr-2021.)
𝐴 = {𝑓 ∣ (𝑓:dom 𝑓⟶(𝒫 (𝒫 dom 𝑓 ∖ {∅}) ∖ {∅}) ∧ ∀𝑝 ∈ dom 𝑓𝑛 ∈ (𝑓𝑝)(𝑝𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝑓(𝑛𝑠𝑠 ∈ (𝑓𝑝))))}       (𝐹𝑉 → (𝐹𝐴 ↔ (𝐹:dom 𝐹⟶(𝒫 (𝒫 dom 𝐹 ∖ {∅}) ∖ {∅}) ∧ ∀𝑝 ∈ dom 𝐹𝑛 ∈ (𝐹𝑝)(𝑝𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝐹(𝑛𝑠𝑠 ∈ (𝐹𝑝))))))

Theoremgneispace3 37342* The predicate that 𝐹 is a (generic) Seifert And Threlfall neighborhood space. (Contributed by RP, 15-Apr-2021.)
𝐴 = {𝑓 ∣ (𝑓:dom 𝑓⟶(𝒫 (𝒫 dom 𝑓 ∖ {∅}) ∖ {∅}) ∧ ∀𝑝 ∈ dom 𝑓𝑛 ∈ (𝑓𝑝)(𝑝𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝑓(𝑛𝑠𝑠 ∈ (𝑓𝑝))))}       (𝐹𝑉 → (𝐹𝐴 ↔ ((Fun 𝐹 ∧ ran 𝐹 ⊆ (𝒫 (𝒫 dom 𝐹 ∖ {∅}) ∖ {∅})) ∧ ∀𝑝 ∈ dom 𝐹𝑛 ∈ (𝐹𝑝)(𝑝𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝐹(𝑛𝑠𝑠 ∈ (𝐹𝑝))))))

Theoremgneispace 37343* The predicate that 𝐹 is a (generic) Seifert And Threlfall neighborhood space. (Contributed by RP, 14-Apr-2021.)
𝐴 = {𝑓 ∣ (𝑓:dom 𝑓⟶(𝒫 (𝒫 dom 𝑓 ∖ {∅}) ∖ {∅}) ∧ ∀𝑝 ∈ dom 𝑓𝑛 ∈ (𝑓𝑝)(𝑝𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝑓(𝑛𝑠𝑠 ∈ (𝑓𝑝))))}       (𝐹𝑉 → (𝐹𝐴 ↔ (Fun 𝐹 ∧ ran 𝐹 ⊆ 𝒫 𝒫 dom 𝐹 ∧ ∀𝑝 ∈ dom 𝐹((𝐹𝑝) ≠ ∅ ∧ ∀𝑛 ∈ (𝐹𝑝)(𝑝𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝐹(𝑛𝑠𝑠 ∈ (𝐹𝑝)))))))

Theoremgneispacef 37344* A generic neighborhood space is a function with a range that is a subset of the powerset of the powerset of its domain. (Contributed by RP, 15-Apr-2021.)
𝐴 = {𝑓 ∣ (𝑓:dom 𝑓⟶(𝒫 (𝒫 dom 𝑓 ∖ {∅}) ∖ {∅}) ∧ ∀𝑝 ∈ dom 𝑓𝑛 ∈ (𝑓𝑝)(𝑝𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝑓(𝑛𝑠𝑠 ∈ (𝑓𝑝))))}       (𝐹𝐴𝐹:dom 𝐹⟶(𝒫 (𝒫 dom 𝐹 ∖ {∅}) ∖ {∅}))

Theoremgneispacef2 37345* A generic neighborhood space is a function with a range that is a subset of the powerset of the powerset of its domain. (Contributed by RP, 15-Apr-2021.)
𝐴 = {𝑓 ∣ (𝑓:dom 𝑓⟶(𝒫 (𝒫 dom 𝑓 ∖ {∅}) ∖ {∅}) ∧ ∀𝑝 ∈ dom 𝑓𝑛 ∈ (𝑓𝑝)(𝑝𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝑓(𝑛𝑠𝑠 ∈ (𝑓𝑝))))}       (𝐹𝐴𝐹:dom 𝐹⟶𝒫 𝒫 dom 𝐹)

Theoremgneispacefun 37346* A generic neighborhood space is a function. (Contributed by RP, 15-Apr-2021.)
𝐴 = {𝑓 ∣ (𝑓:dom 𝑓⟶(𝒫 (𝒫 dom 𝑓 ∖ {∅}) ∖ {∅}) ∧ ∀𝑝 ∈ dom 𝑓𝑛 ∈ (𝑓𝑝)(𝑝𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝑓(𝑛𝑠𝑠 ∈ (𝑓𝑝))))}       (𝐹𝐴 → Fun 𝐹)

Theoremgneispacern 37347* A generic neighborhood space has a range that is a subset of the powerset of the powerset of its domain. (Contributed by RP, 15-Apr-2021.)
𝐴 = {𝑓 ∣ (𝑓:dom 𝑓⟶(𝒫 (𝒫 dom 𝑓 ∖ {∅}) ∖ {∅}) ∧ ∀𝑝 ∈ dom 𝑓𝑛 ∈ (𝑓𝑝)(𝑝𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝑓(𝑛𝑠𝑠 ∈ (𝑓𝑝))))}       (𝐹𝐴 → ran 𝐹 ⊆ (𝒫 (𝒫 dom 𝐹 ∖ {∅}) ∖ {∅}))

Theoremgneispacern2 37348* A generic neighborhood space has a range that is a subset of the powerset of the powerset of its domain. (Contributed by RP, 15-Apr-2021.)
𝐴 = {𝑓 ∣ (𝑓:dom 𝑓⟶(𝒫 (𝒫 dom 𝑓 ∖ {∅}) ∖ {∅}) ∧ ∀𝑝 ∈ dom 𝑓𝑛 ∈ (𝑓𝑝)(𝑝𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝑓(𝑛𝑠𝑠 ∈ (𝑓𝑝))))}       (𝐹𝐴 → ran 𝐹 ⊆ 𝒫 𝒫 dom 𝐹)

Theoremgneispace0nelrn 37349* A generic neighborhood space has a non-empty set of neighborhoods for every point in its domain. (Contributed by RP, 15-Apr-2021.)
𝐴 = {𝑓 ∣ (𝑓:dom 𝑓⟶(𝒫 (𝒫 dom 𝑓 ∖ {∅}) ∖ {∅}) ∧ ∀𝑝 ∈ dom 𝑓𝑛 ∈ (𝑓𝑝)(𝑝𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝑓(𝑛𝑠𝑠 ∈ (𝑓𝑝))))}       (𝐹𝐴 → ∀𝑝 ∈ dom 𝐹(𝐹𝑝) ≠ ∅)

Theoremgneispace0nelrn2 37350* A generic neighborhood space has a non-empty set of neighborhoods for every point in its domain. (Contributed by RP, 15-Apr-2021.)
𝐴 = {𝑓 ∣ (𝑓:dom 𝑓⟶(𝒫 (𝒫 dom 𝑓 ∖ {∅}) ∖ {∅}) ∧ ∀𝑝 ∈ dom 𝑓𝑛 ∈ (𝑓𝑝)(𝑝𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝑓(𝑛𝑠𝑠 ∈ (𝑓𝑝))))}       ((𝐹𝐴𝑃 ∈ dom 𝐹) → (𝐹𝑃) ≠ ∅)

Theoremgneispace0nelrn3 37351* A generic neighborhood space has a non-empty set of neighborhoods for every point in its domain. (Contributed by RP, 15-Apr-2021.)
𝐴 = {𝑓 ∣ (𝑓:dom 𝑓⟶(𝒫 (𝒫 dom 𝑓 ∖ {∅}) ∖ {∅}) ∧ ∀𝑝 ∈ dom 𝑓𝑛 ∈ (𝑓𝑝)(𝑝𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝑓(𝑛𝑠𝑠 ∈ (𝑓𝑝))))}       (𝐹𝐴 → ¬ ∅ ∈ ran 𝐹)

Theoremgneispaceel 37352* Every neighborhood of a point in a generic neighborhood space contains that point. (Contributed by RP, 15-Apr-2021.)
𝐴 = {𝑓 ∣ (𝑓:dom 𝑓⟶(𝒫 (𝒫 dom 𝑓 ∖ {∅}) ∖ {∅}) ∧ ∀𝑝 ∈ dom 𝑓𝑛 ∈ (𝑓𝑝)(𝑝𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝑓(𝑛𝑠𝑠 ∈ (𝑓𝑝))))}       (𝐹𝐴 → ∀𝑝 ∈ dom 𝐹𝑛 ∈ (𝐹𝑝)𝑝𝑛)

Theoremgneispaceel2 37353* Every neighborhood of a point in a generic neighborhood space contains that point. (Contributed by RP, 15-Apr-2021.)
𝐴 = {𝑓 ∣ (𝑓:dom 𝑓⟶(𝒫 (𝒫 dom 𝑓 ∖ {∅}) ∖ {∅}) ∧ ∀𝑝 ∈ dom 𝑓𝑛 ∈ (𝑓𝑝)(𝑝𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝑓(𝑛𝑠𝑠 ∈ (𝑓𝑝))))}       ((𝐹𝐴𝑃 ∈ dom 𝐹𝑁 ∈ (𝐹𝑃)) → 𝑃𝑁)

Theoremgneispacess 37354* All supersets of a neighborhood of a point (limited to the domain of the neighborhood space) are also neighborhoods of that point. (Contributed by RP, 15-Apr-2021.)
𝐴 = {𝑓 ∣ (𝑓:dom 𝑓⟶(𝒫 (𝒫 dom 𝑓 ∖ {∅}) ∖ {∅}) ∧ ∀𝑝 ∈ dom 𝑓𝑛 ∈ (𝑓𝑝)(𝑝𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝑓(𝑛𝑠𝑠 ∈ (𝑓𝑝))))}       (𝐹𝐴 → ∀𝑝 ∈ dom 𝐹𝑛 ∈ (𝐹𝑝)∀𝑠 ∈ 𝒫 dom 𝐹(𝑛𝑠𝑠 ∈ (𝐹𝑝)))

Theoremgneispacess2 37355* All supersets of a neighborhood of a point (limited to the domain of the neighborhood space) are also neighborhoods of that point. (Contributed by RP, 15-Apr-2021.)
𝐴 = {𝑓 ∣ (𝑓:dom 𝑓⟶(𝒫 (𝒫 dom 𝑓 ∖ {∅}) ∖ {∅}) ∧ ∀𝑝 ∈ dom 𝑓𝑛 ∈ (𝑓𝑝)(𝑝𝑛 ∧ ∀𝑠 ∈ 𝒫 dom 𝑓(𝑛𝑠𝑠 ∈ (𝑓𝑝))))}       (((𝐹𝐴𝑃 ∈ dom 𝐹) ∧ (𝑁 ∈ (𝐹𝑃) ∧ 𝑆 ∈ 𝒫 dom 𝐹𝑁𝑆)) → 𝑆 ∈ (𝐹𝑃))

20.26.5  Exploring Higher Homotopy via Kerodon

See https://kerodon.net/ for a work in progress by Jacob Lurie.

20.26.5.1  Simplicial Sets

See https://kerodon.net/tag/0004 for introduction to the topological simplex of dimension 𝑁.

Theoremk0004lem1 37356 Application of ssin 3700 to range of a function. (Contributed by RP, 1-Apr-2021.)
(𝐷 = (𝐵𝐶) → ((𝐹:𝐴𝐵 ∧ (𝐹𝐴) ⊆ 𝐶) ↔ 𝐹:𝐴𝐷))

Theoremk0004lem2 37357 A mapping with a particular restricted range is also a mapping to that range. (Contributed by RP, 1-Apr-2021.)
((𝐴𝑈𝐵𝑉𝐶𝐵) → ((𝐹 ∈ (𝐵𝑚 𝐴) ∧ (𝐹𝐴) ⊆ 𝐶) ↔ 𝐹 ∈ (𝐶𝑚 𝐴)))

Theoremk0004lem3 37358 When the value of a mapping on a singleton is known, the mapping is a a completely known singleton. (Contributed by RP, 2-Apr-2021.)
((𝐴𝑈𝐵𝑉𝐶𝐵) → ((𝐹 ∈ (𝐵𝑚 {𝐴}) ∧ (𝐹𝐴) = 𝐶) ↔ 𝐹 = {⟨𝐴, 𝐶⟩}))

Theoremk0004val 37359* The topological simplex of dimension 𝑁 is the set of real vectors where the components are nonnegative and sum to 1. (Contributed by RP, 29-Mar-2021.)
𝐴 = (𝑛 ∈ ℕ0 ↦ {𝑡 ∈ ((0[,]1) ↑𝑚 (1...(𝑛 + 1))) ∣ Σ𝑘 ∈ (1...(𝑛 + 1))(𝑡𝑘) = 1})       (𝑁 ∈ ℕ0 → (𝐴𝑁) = {𝑡 ∈ ((0[,]1) ↑𝑚 (1...(𝑁 + 1))) ∣ Σ𝑘 ∈ (1...(𝑁 + 1))(𝑡𝑘) = 1})

Theoremk0004ss1 37360* The topological simplex of dimension 𝑁 is a subset of the real vectors of dimension (𝑁 + 1). (Contributed by RP, 29-Mar-2021.)
𝐴 = (𝑛 ∈ ℕ0 ↦ {𝑡 ∈ ((0[,]1) ↑𝑚 (1...(𝑛 + 1))) ∣ Σ𝑘 ∈ (1...(𝑛 + 1))(𝑡𝑘) = 1})       (𝑁 ∈ ℕ0 → (𝐴𝑁) ⊆ (ℝ ↑𝑚 (1...(𝑁 + 1))))

Theoremk0004ss2 37361* The topological simplex of dimension 𝑁 is a subset of the base set of a real vector space of dimension (𝑁 + 1). (Contributed by RP, 29-Mar-2021.)
𝐴 = (𝑛 ∈ ℕ0 ↦ {𝑡 ∈ ((0[,]1) ↑𝑚 (1...(𝑛 + 1))) ∣ Σ𝑘 ∈ (1...(𝑛 + 1))(𝑡𝑘) = 1})       (𝑁 ∈ ℕ0 → (𝐴𝑁) ⊆ (Base‘(ℝ^‘(1...(𝑁 + 1)))))

Theoremk0004ss3 37362* The topological simplex of dimension 𝑁 is a subset of the base set of Euclidean space of dimension (𝑁 + 1). (Contributed by RP, 29-Mar-2021.)
𝐴 = (𝑛 ∈ ℕ0 ↦ {𝑡 ∈ ((0[,]1) ↑𝑚 (1...(𝑛 + 1))) ∣ Σ𝑘 ∈ (1...(𝑛 + 1))(𝑡𝑘) = 1})       (𝑁 ∈ ℕ0 → (𝐴𝑁) ⊆ (Base‘(𝔼hil‘(𝑁 + 1))))

Theoremk0004val0 37363* The topological simplex of dimension 0 is a singleton. (Contributed by RP, 2-Apr-2021.)
𝐴 = (𝑛 ∈ ℕ0 ↦ {𝑡 ∈ ((0[,]1) ↑𝑚 (1...(𝑛 + 1))) ∣ Σ𝑘 ∈ (1...(𝑛 + 1))(𝑡𝑘) = 1})       (𝐴‘0) = {{⟨1, 1⟩}}

20.27  Mathbox for Stanislas Polu

Theoreminductionexd 37364 Simple induction example. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝑁 ∈ ℕ → 3 ∥ ((4↑𝑁) + 5))

20.27.1  IMO Problems

20.27.1.1  IMO 1972 B2

Theoremwwlemuld 37365 Natural deduction form of lemul2d 11661. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑𝐴 ∈ ℝ)    &   (𝜑𝐵 ∈ ℝ)    &   (𝜑𝐶 ∈ ℝ)    &   (𝜑 → (𝐶 · 𝐴) ≤ (𝐶 · 𝐵))    &   (𝜑 → 0 < 𝐶)       (𝜑𝐴𝐵)

Theoremleeq1d 37366 Specialization of breq1d 4491 to reals and less than. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑𝐴𝐶)    &   (𝜑𝐴 = 𝐵)    &   (𝜑𝐴 ∈ ℝ)    &   (𝜑𝐶 ∈ ℝ)       (𝜑𝐵𝐶)

Theoremleeq2d 37367 Specialization of breq2d 4493 to reals and less than. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑𝐴𝐶)    &   (𝜑𝐶 = 𝐷)    &   (𝜑𝐴 ∈ ℝ)    &   (𝜑𝐶 ∈ ℝ)       (𝜑𝐴𝐷)

Theoremabsmulrposd 37368 Specialization of absmuld with absidd 13871. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑 → 0 ≤ 𝐴)    &   (𝜑𝐴 ∈ ℝ)    &   (𝜑𝐵 ∈ ℝ)       (𝜑 → (abs‘(𝐴 · 𝐵)) = (𝐴 · (abs‘𝐵)))

Theoremimadisjld 37369 Natural dduction form of one side of imadisj 5294. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑 → (dom 𝐴𝐵) = ∅)       (𝜑 → (𝐴𝐵) = ∅)

Theoremimadisjlnd 37370 Natural deduction form of one negated side of imadisj 5294. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑 → (dom 𝐴𝐵) ≠ ∅)       (𝜑 → (𝐴𝐵) ≠ ∅)

Theoremwnefimgd 37371 The image of a mapping from A is non empty if A is non empty. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑𝐴 ≠ ∅)    &   (𝜑𝐹:𝐴𝐵)       (𝜑 → (𝐹𝐴) ≠ ∅)

Theoremfco2d 37372 Natural deduction form of fco2 5862. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑𝐺:𝐴𝐵)    &   (𝜑 → (𝐹𝐵):𝐵𝐶)       (𝜑 → (𝐹𝐺):𝐴𝐶)

Theoremsuprubd 37373* Natural deduction form of suprubd 37373. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑𝐴 ⊆ ℝ)    &   (𝜑𝐴 ≠ ∅)    &   (𝜑 → ∃𝑥 ∈ ℝ ∀𝑦𝐴 𝑦𝑥)    &   (𝜑𝐵𝐴)       (𝜑𝐵 ≤ sup(𝐴, ℝ, < ))

Theoremsuprcld 37374* Natural deduction form of suprcl 10739. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑𝐴 ⊆ ℝ)    &   (𝜑𝐴 ≠ ∅)    &   (𝜑 → ∃𝑥 ∈ ℝ ∀𝑦𝐴 𝑦𝑥)       (𝜑 → sup(𝐴, ℝ, < ) ∈ ℝ)

Theoremfvco3d 37375 Natural deduction form of fvco3 6074. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑𝐺:𝐴𝐵)    &   (𝜑𝐶𝐴)       (𝜑 → ((𝐹𝐺)‘𝐶) = (𝐹‘(𝐺𝐶)))

Theoremwfximgfd 37376 The value of a function on its domain is in the image of the function. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑𝐶𝐴)    &   (𝜑𝐹:𝐴𝐵)       (𝜑 → (𝐹𝐶) ∈ (𝐹𝐴))

Theoremextoimad 37377* If |f(x)| <= C for all x then it applies to all x in the image of |f(x)| (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑𝐹:ℝ⟶ℝ)    &   (𝜑 → ∀𝑦 ∈ ℝ (abs‘(𝐹𝑦)) ≤ 𝐶)       (𝜑 → ∀𝑥 ∈ (abs “ (𝐹 “ ℝ))𝑥𝐶)

Theoremimo72b2lem0 37378* Lemma for imo72b2 37388. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑𝐹:ℝ⟶ℝ)    &   (𝜑𝐺:ℝ⟶ℝ)    &   (𝜑𝐴 ∈ ℝ)    &   (𝜑𝐵 ∈ ℝ)    &   (𝜑 → ((𝐹‘(𝐴 + 𝐵)) + (𝐹‘(𝐴𝐵))) = (2 · ((𝐹𝐴) · (𝐺𝐵))))    &   (𝜑 → ∀𝑦 ∈ ℝ (abs‘(𝐹𝑦)) ≤ 1)       (𝜑 → ((abs‘(𝐹𝐴)) · (abs‘(𝐺𝐵))) ≤ sup((abs “ (𝐹 “ ℝ)), ℝ, < ))

Theoremsuprleubrd 37379* Natural deduction form of specialized suprleub 10743. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑𝐴 ⊆ ℝ)    &   (𝜑𝐴 ≠ ∅)    &   (𝜑 → ∃𝑥 ∈ ℝ ∀𝑦𝐴 𝑦𝑥)    &   (𝜑𝐵 ∈ ℝ)    &   (𝜑 → ∀𝑧𝐴 𝑧𝐵)       (𝜑 → sup(𝐴, ℝ, < ) ≤ 𝐵)

Theoremimo72b2lem2 37380* Lemma for imo72b2 37388. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑𝐹:ℝ⟶ℝ)    &   (𝜑𝐶 ∈ ℝ)    &   (𝜑 → ∀𝑧 ∈ ℝ (abs‘(𝐹𝑧)) ≤ 𝐶)       (𝜑 → sup((abs “ (𝐹 “ ℝ)), ℝ, < ) ≤ 𝐶)

Theoremsyldbl2 37381 Stacked hypotheseis implies goal. (Contributed by Stanislas Polu, 9-Mar-2020.)
((𝜑𝜓) → (𝜓𝜃))       ((𝜑𝜓) → 𝜃)

Theoremfunfvima2d 37382 A function's value in a preimage belongs to the image. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑𝐹:𝐴𝐵)       ((𝜑𝑥𝐴) → (𝐹𝑥) ∈ (𝐹𝐴))

Theoremsuprlubrd 37383* Natural deduction form of specialized suprlub 10741. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑𝐴 ⊆ ℝ)    &   (𝜑𝐴 ≠ ∅)    &   (𝜑 → ∃𝑥 ∈ ℝ ∀𝑦𝐴 𝑦𝑥)    &   (𝜑𝐵 ∈ ℝ)    &   (𝜑 → ∃𝑧𝐴 𝐵 < 𝑧)       (𝜑𝐵 < sup(𝐴, ℝ, < ))

Theoremimo72b2lem1 37384* Lemma for imo72b2 37388. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑𝐹:ℝ⟶ℝ)    &   (𝜑 → ∃𝑥 ∈ ℝ (𝐹𝑥) ≠ 0)    &   (𝜑 → ∀𝑦 ∈ ℝ (abs‘(𝐹𝑦)) ≤ 1)       (𝜑 → 0 < sup((abs “ (𝐹 “ ℝ)), ℝ, < ))

Theoremlemuldiv3d 37385 'Less than or equal to' relationship between division and multiplication. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑 → (𝐵 · 𝐴) ≤ 𝐶)    &   (𝜑 → 0 < 𝐴)    &   (𝜑𝐴 ∈ ℝ)    &   (𝜑𝐵 ∈ ℝ)    &   (𝜑𝐶 ∈ ℝ)       (𝜑𝐵 ≤ (𝐶 / 𝐴))

Theoremlemuldiv4d 37386 'Less than or equal to' relationship between division and multiplication. (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑𝐵 ≤ (𝐶 / 𝐴))    &   (𝜑 → 0 < 𝐴)    &   (𝜑𝐴 ∈ ℝ)    &   (𝜑𝐵 ∈ ℝ)    &   (𝜑𝐶 ∈ ℝ)       (𝜑 → (𝐵 · 𝐴) ≤ 𝐶)

Theoremrspcdvinvd 37387* If something is true for all then it's true for some class. (Contributed by Stanislas Polu, 9-Mar-2020.)
((𝜑𝑥 = 𝐴) → (𝜓𝜒))    &   (𝜑𝐴𝐵)    &   (𝜑 → ∀𝑥𝐵 𝜓)       (𝜑𝜒)

Theoremimo72b2 37388* IMO 1972 B2. (14th International Mathemahics Olympiad in Poland, problem B2). (Contributed by Stanislas Polu, 9-Mar-2020.)
(𝜑𝐹:ℝ⟶ℝ)    &   (𝜑𝐺:ℝ⟶ℝ)    &   (𝜑𝐵 ∈ ℝ)    &   (𝜑 → ∀𝑢 ∈ ℝ ∀𝑣 ∈ ℝ ((𝐹‘(𝑢 + 𝑣)) + (𝐹‘(𝑢𝑣))) = (2 · ((𝐹𝑢) · (𝐺𝑣))))    &   (𝜑 → ∀𝑦 ∈ ℝ (abs‘(𝐹𝑦)) ≤ 1)    &   (𝜑 → ∃𝑥 ∈ ℝ (𝐹𝑥) ≠ 0)       (𝜑 → (abs‘(𝐺𝐵)) ≤ 1)

20.27.2  INT Inequalities Proof Generator

This section formalizes theorems necessary to reproduce the equality and inequality generator described in "Neural Theorem Proving on Inequality Problems" http://aitp-conference.org/2020/abstract/paper_18.pdf.

Other theorems required: 0red 9800 1red 9814 readdcld 9828 remulcld 9829 eqcomd 2520.

(𝜑𝐵 ∈ ℝ)    &   (𝜑𝐶 ∈ ℝ)    &   (𝜑𝐴 = 𝐵)       (𝜑 → (𝐵 + 𝐶) = (𝐶 + 𝐴))

(𝜑𝐴 ∈ ℝ)    &   (𝜑𝐶 ∈ ℝ)    &   (𝜑𝐷 ∈ ℝ)    &   (𝜑𝐴 = 𝐵)       (𝜑 → (𝐵 + (𝐶 + 𝐷)) = ((𝐴 + 𝐶) + 𝐷))

(𝜑𝐴 ∈ ℝ)    &   (𝜑𝐴 = 𝐵)       (𝜑 → 0 = (𝐴𝐵))

Theoremint-mulcomd 37392 MultiplicationCommutativity generator rule. (Contributed by Stanislas Polu, 7-Apr-2020.)
(𝜑𝐵 ∈ ℝ)    &   (𝜑𝐶 ∈ ℝ)    &   (𝜑𝐴 = 𝐵)       (𝜑 → (𝐵 · 𝐶) = (𝐶 · 𝐴))

Theoremint-mulassocd 37393 MultiplicationAssociativity generator rule. (Contributed by Stanislas Polu, 7-Apr-2020.)
(𝜑𝐵 ∈ ℝ)    &   (𝜑𝐶 ∈ ℝ)    &   (𝜑𝐷 ∈ ℝ)    &   (𝜑𝐴 = 𝐵)       (𝜑 → (𝐵 · (𝐶 · 𝐷)) = ((𝐴 · 𝐶) · 𝐷))

Theoremint-mulsimpd 37394 MultiplicationSimplification generator rule. (Contributed by Stanislas Polu, 7-Apr-2020.)
(𝜑𝐵 ∈ ℝ)    &   (𝜑𝐴 = 𝐵)    &   (𝜑𝐵 ≠ 0)       (𝜑 → 1 = (𝐴 / 𝐵))

Theoremint-leftdistd 37395 AdditionMultiplicationLeftDistribution generator rule. (Contributed by Stanislas Polu, 7-Apr-2020.)
(𝜑𝐵 ∈ ℝ)    &   (𝜑𝐶 ∈ ℝ)    &   (𝜑𝐷 ∈ ℝ)    &   (𝜑𝐴 = 𝐵)       (𝜑 → ((𝐶 + 𝐷) · 𝐵) = ((𝐶 · 𝐴) + (𝐷 · 𝐴)))

Theoremint-rightdistd 37396 AdditionMultiplicationRightDistribution generator rule. (Contributed by Stanislas Polu, 7-Apr-2020.)
(𝜑𝐵 ∈ ℝ)    &   (𝜑𝐶 ∈ ℝ)    &   (𝜑𝐷 ∈ ℝ)    &   (𝜑𝐴 = 𝐵)       (𝜑 → (𝐵 · (𝐶 + 𝐷)) = ((𝐴 · 𝐶) + (𝐴 · 𝐷)))

Theoremint-sqdefd 37397 SquareDefinition generator rule. (Contributed by Stanislas Polu, 7-Apr-2020.)
(𝜑𝐵 ∈ ℝ)    &   (𝜑𝐴 = 𝐵)       (𝜑 → (𝐴 · 𝐵) = (𝐴↑2))

Theoremint-mul11d 37398 First MultiplicationOne generator rule. (Contributed by Stanislas Polu, 7-Apr-2020.)
(𝜑𝐴 ∈ ℝ)    &   (𝜑𝐴 = 𝐵)       (𝜑 → (𝐴 · 1) = 𝐵)

Theoremint-mul12d 37399 Second MultiplicationOne generator rule. (Contributed by Stanislas Polu, 7-Apr-2020.)
(𝜑𝐴 ∈ ℝ)    &   (𝜑𝐴 = 𝐵)       (𝜑 → (1 · 𝐴) = 𝐵)