P. 414 of Theorem List - Metamath Proof Explorer

Theorem List for Metamath Proof Explorer - 41301-41400   *Has distinct variable group(s)

Type	Label	Description
Statement
Theorem	metakunt10 41301*	C is the right inverse for A. (Contributed by metakunt, 24-May-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ 𝐴 = (𝑥 ∈ (1...𝑀) ↦ if(𝑥 = 𝐼, 𝑀, if(𝑥 < 𝐼, 𝑥, (𝑥 − 1))))    &   ⊢ 𝐶 = (𝑦 ∈ (1...𝑀) ↦ if(𝑦 = 𝑀, 𝐼, if(𝑦 < 𝐼, 𝑦, (𝑦 + 1))))    &   ⊢ (𝜑 → 𝑋 ∈ (1...𝑀))    ⇒   ⊢ ((𝜑 ∧ 𝑋 = 𝑀) → (𝐴‘(𝐶‘𝑋)) = 𝑋)
Theorem	metakunt11 41302*	C is the right inverse for A. (Contributed by metakunt, 24-May-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ 𝐴 = (𝑥 ∈ (1...𝑀) ↦ if(𝑥 = 𝐼, 𝑀, if(𝑥 < 𝐼, 𝑥, (𝑥 − 1))))    &   ⊢ 𝐶 = (𝑦 ∈ (1...𝑀) ↦ if(𝑦 = 𝑀, 𝐼, if(𝑦 < 𝐼, 𝑦, (𝑦 + 1))))    &   ⊢ (𝜑 → 𝑋 ∈ (1...𝑀))    ⇒   ⊢ ((𝜑 ∧ 𝑋 < 𝐼) → (𝐴‘(𝐶‘𝑋)) = 𝑋)
Theorem	metakunt12 41303*	C is the right inverse for A. (Contributed by metakunt, 25-May-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ 𝐴 = (𝑥 ∈ (1...𝑀) ↦ if(𝑥 = 𝐼, 𝑀, if(𝑥 < 𝐼, 𝑥, (𝑥 − 1))))    &   ⊢ 𝐶 = (𝑦 ∈ (1...𝑀) ↦ if(𝑦 = 𝑀, 𝐼, if(𝑦 < 𝐼, 𝑦, (𝑦 + 1))))    &   ⊢ (𝜑 → 𝑋 ∈ (1...𝑀))    ⇒   ⊢ ((𝜑 ∧ ¬ (𝑋 = 𝑀 ∨ 𝑋 < 𝐼)) → (𝐴‘(𝐶‘𝑋)) = 𝑋)
Theorem	metakunt13 41304*	C is the right inverse for A. (Contributed by metakunt, 25-May-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ 𝐴 = (𝑥 ∈ (1...𝑀) ↦ if(𝑥 = 𝐼, 𝑀, if(𝑥 < 𝐼, 𝑥, (𝑥 − 1))))    &   ⊢ 𝐶 = (𝑦 ∈ (1...𝑀) ↦ if(𝑦 = 𝑀, 𝐼, if(𝑦 < 𝐼, 𝑦, (𝑦 + 1))))    &   ⊢ (𝜑 → 𝑋 ∈ (1...𝑀))    ⇒   ⊢ (𝜑 → (𝐴‘(𝐶‘𝑋)) = 𝑋)
Theorem	metakunt14 41305*	A is a primitive permutation that moves the I-th element to the end and C is its inverse that moves the last element back to the I-th position. (Contributed by metakunt, 25-May-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ 𝐴 = (𝑥 ∈ (1...𝑀) ↦ if(𝑥 = 𝐼, 𝑀, if(𝑥 < 𝐼, 𝑥, (𝑥 − 1))))    &   ⊢ 𝐶 = (𝑦 ∈ (1...𝑀) ↦ if(𝑦 = 𝑀, 𝐼, if(𝑦 < 𝐼, 𝑦, (𝑦 + 1))))    ⇒   ⊢ (𝜑 → (𝐴:(1...𝑀)–1-1-onto→(1...𝑀) ∧ ◡𝐴 = 𝐶))
Theorem	metakunt15 41306*	Construction of another permutation. (Contributed by metakunt, 25-May-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ 𝐹 = (𝑥 ∈ (1...(𝐼 − 1)) ↦ (𝑥 + (𝑀 − 𝐼)))    ⇒   ⊢ (𝜑 → 𝐹:(1...(𝐼 − 1))–1-1-onto→(((𝑀 − 𝐼) + 1)...(𝑀 − 1)))
Theorem	metakunt16 41307*	Construction of another permutation. (Contributed by metakunt, 25-May-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ 𝐹 = (𝑥 ∈ (𝐼...(𝑀 − 1)) ↦ (𝑥 + (1 − 𝐼)))    ⇒   ⊢ (𝜑 → 𝐹:(𝐼...(𝑀 − 1))–1-1-onto→(1...(𝑀 − 𝐼)))
Theorem	metakunt17 41308	The union of three disjoint bijections is a bijection. (Contributed by metakunt, 28-May-2024.)
⊢ (𝜑 → 𝐺:𝐴–1-1-onto→𝑋)    &   ⊢ (𝜑 → 𝐻:𝐵–1-1-onto→𝑌)    &   ⊢ (𝜑 → 𝐼:𝐶–1-1-onto→𝑍)    &   ⊢ (𝜑 → (𝐴 ∩ 𝐵) = ∅)    &   ⊢ (𝜑 → (𝐴 ∩ 𝐶) = ∅)    &   ⊢ (𝜑 → (𝐵 ∩ 𝐶) = ∅)    &   ⊢ (𝜑 → (𝑋 ∩ 𝑌) = ∅)    &   ⊢ (𝜑 → (𝑋 ∩ 𝑍) = ∅)    &   ⊢ (𝜑 → (𝑌 ∩ 𝑍) = ∅)    &   ⊢ (𝜑 → 𝐹 = ((𝐺 ∪ 𝐻) ∪ 𝐼))    &   ⊢ (𝜑 → 𝐷 = ((𝐴 ∪ 𝐵) ∪ 𝐶))    &   ⊢ (𝜑 → 𝑊 = ((𝑋 ∪ 𝑌) ∪ 𝑍))    ⇒   ⊢ (𝜑 → 𝐹:𝐷–1-1-onto→𝑊)
Theorem	metakunt18 41309	Disjoint domains and codomains. (Contributed by metakunt, 28-May-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    ⇒   ⊢ (𝜑 → ((((1...(𝐼 − 1)) ∩ (𝐼...(𝑀 − 1))) = ∅ ∧ ((1...(𝐼 − 1)) ∩ {𝑀}) = ∅ ∧ ((𝐼...(𝑀 − 1)) ∩ {𝑀}) = ∅) ∧ (((((𝑀 − 𝐼) + 1)...(𝑀 − 1)) ∩ (1...(𝑀 − 𝐼))) = ∅ ∧ ((((𝑀 − 𝐼) + 1)...(𝑀 − 1)) ∩ {𝑀}) = ∅ ∧ ((1...(𝑀 − 𝐼)) ∩ {𝑀}) = ∅)))
Theorem	metakunt19 41310*	Domains on restrictions of functions. (Contributed by metakunt, 28-May-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ 𝐵 = (𝑥 ∈ (1...𝑀) ↦ if(𝑥 = 𝑀, 𝑀, if(𝑥 < 𝐼, (𝑥 + (𝑀 − 𝐼)), (𝑥 + (1 − 𝐼)))))    &   ⊢ 𝐶 = (𝑥 ∈ (1...(𝐼 − 1)) ↦ (𝑥 + (𝑀 − 𝐼)))    &   ⊢ 𝐷 = (𝑥 ∈ (𝐼...(𝑀 − 1)) ↦ (𝑥 + (1 − 𝐼)))    ⇒   ⊢ (𝜑 → ((𝐶 Fn (1...(𝐼 − 1)) ∧ 𝐷 Fn (𝐼...(𝑀 − 1)) ∧ (𝐶 ∪ 𝐷) Fn ((1...(𝐼 − 1)) ∪ (𝐼...(𝑀 − 1)))) ∧ {⟨𝑀, 𝑀⟩} Fn {𝑀}))
Theorem	metakunt20 41311*	Show that B coincides on the union of bijections of functions. (Contributed by metakunt, 28-May-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ 𝐵 = (𝑥 ∈ (1...𝑀) ↦ if(𝑥 = 𝑀, 𝑀, if(𝑥 < 𝐼, (𝑥 + (𝑀 − 𝐼)), (𝑥 + (1 − 𝐼)))))    &   ⊢ 𝐶 = (𝑥 ∈ (1...(𝐼 − 1)) ↦ (𝑥 + (𝑀 − 𝐼)))    &   ⊢ 𝐷 = (𝑥 ∈ (𝐼...(𝑀 − 1)) ↦ (𝑥 + (1 − 𝐼)))    &   ⊢ (𝜑 → 𝑋 ∈ (1...𝑀))    &   ⊢ (𝜑 → 𝑋 = 𝑀)    ⇒   ⊢ (𝜑 → (𝐵‘𝑋) = (((𝐶 ∪ 𝐷) ∪ {⟨𝑀, 𝑀⟩})‘𝑋))
Theorem	metakunt21 41312*	Show that B coincides on the union of bijections of functions. (Contributed by metakunt, 28-May-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ 𝐵 = (𝑥 ∈ (1...𝑀) ↦ if(𝑥 = 𝑀, 𝑀, if(𝑥 < 𝐼, (𝑥 + (𝑀 − 𝐼)), (𝑥 + (1 − 𝐼)))))    &   ⊢ 𝐶 = (𝑥 ∈ (1...(𝐼 − 1)) ↦ (𝑥 + (𝑀 − 𝐼)))    &   ⊢ 𝐷 = (𝑥 ∈ (𝐼...(𝑀 − 1)) ↦ (𝑥 + (1 − 𝐼)))    &   ⊢ (𝜑 → 𝑋 ∈ (1...𝑀))    &   ⊢ (𝜑 → ¬ 𝑋 = 𝑀)    &   ⊢ (𝜑 → 𝑋 < 𝐼)    ⇒   ⊢ (𝜑 → (𝐵‘𝑋) = (((𝐶 ∪ 𝐷) ∪ {⟨𝑀, 𝑀⟩})‘𝑋))
Theorem	metakunt22 41313*	Show that B coincides on the union of bijections of functions. (Contributed by metakunt, 28-May-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ 𝐵 = (𝑥 ∈ (1...𝑀) ↦ if(𝑥 = 𝑀, 𝑀, if(𝑥 < 𝐼, (𝑥 + (𝑀 − 𝐼)), (𝑥 + (1 − 𝐼)))))    &   ⊢ 𝐶 = (𝑥 ∈ (1...(𝐼 − 1)) ↦ (𝑥 + (𝑀 − 𝐼)))    &   ⊢ 𝐷 = (𝑥 ∈ (𝐼...(𝑀 − 1)) ↦ (𝑥 + (1 − 𝐼)))    &   ⊢ (𝜑 → 𝑋 ∈ (1...𝑀))    &   ⊢ (𝜑 → ¬ 𝑋 = 𝑀)    &   ⊢ (𝜑 → ¬ 𝑋 < 𝐼)    ⇒   ⊢ (𝜑 → (𝐵‘𝑋) = (((𝐶 ∪ 𝐷) ∪ {⟨𝑀, 𝑀⟩})‘𝑋))
Theorem	metakunt23 41314*	B coincides on the union of bijections of functions. (Contributed by metakunt, 28-May-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ 𝐵 = (𝑥 ∈ (1...𝑀) ↦ if(𝑥 = 𝑀, 𝑀, if(𝑥 < 𝐼, (𝑥 + (𝑀 − 𝐼)), (𝑥 + (1 − 𝐼)))))    &   ⊢ 𝐶 = (𝑥 ∈ (1...(𝐼 − 1)) ↦ (𝑥 + (𝑀 − 𝐼)))    &   ⊢ 𝐷 = (𝑥 ∈ (𝐼...(𝑀 − 1)) ↦ (𝑥 + (1 − 𝐼)))    &   ⊢ (𝜑 → 𝑋 ∈ (1...𝑀))    ⇒   ⊢ (𝜑 → (𝐵‘𝑋) = (((𝐶 ∪ 𝐷) ∪ {⟨𝑀, 𝑀⟩})‘𝑋))
Theorem	metakunt24 41315	Technical condition such that metakunt17 41308 holds. (Contributed by metakunt, 28-May-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    ⇒   ⊢ (𝜑 → ((((1...(𝐼 − 1)) ∪ (𝐼...(𝑀 − 1))) ∩ {𝑀}) = ∅ ∧ (1...𝑀) = (((1...(𝐼 − 1)) ∪ (𝐼...(𝑀 − 1))) ∪ {𝑀}) ∧ (1...𝑀) = (((((𝑀 − 𝐼) + 1)...(𝑀 − 1)) ∪ (1...(𝑀 − 𝐼))) ∪ {𝑀})))
Theorem	metakunt25 41316*	B is a permutation. (Contributed by metakunt, 28-May-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ 𝐵 = (𝑥 ∈ (1...𝑀) ↦ if(𝑥 = 𝑀, 𝑀, if(𝑥 < 𝐼, (𝑥 + (𝑀 − 𝐼)), (𝑥 + (1 − 𝐼)))))    ⇒   ⊢ (𝜑 → 𝐵:(1...𝑀)–1-1-onto→(1...𝑀))
Theorem	metakunt26 41317*	Construction of one solution of the increment equation system. (Contributed by metakunt, 7-Jul-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ 𝐴 = (𝑥 ∈ (1...𝑀) ↦ if(𝑥 = 𝐼, 𝑀, if(𝑥 < 𝐼, 𝑥, (𝑥 − 1))))    &   ⊢ 𝐶 = (𝑦 ∈ (1...𝑀) ↦ if(𝑦 = 𝑀, 𝐼, if(𝑦 < 𝐼, 𝑦, (𝑦 + 1))))    &   ⊢ 𝐵 = (𝑧 ∈ (1...𝑀) ↦ if(𝑧 = 𝑀, 𝑀, if(𝑧 < 𝐼, (𝑧 + (𝑀 − 𝐼)), (𝑧 + (1 − 𝐼)))))    &   ⊢ (𝜑 → 𝑋 = 𝐼)    ⇒   ⊢ (𝜑 → (𝐶‘(𝐵‘(𝐴‘𝑋))) = 𝑋)
Theorem	metakunt27 41318*	Construction of one solution of the increment equation system. (Contributed by metakunt, 7-Jul-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ (𝜑 → 𝑋 ∈ (1...𝑀))    &   ⊢ 𝐴 = (𝑥 ∈ (1...𝑀) ↦ if(𝑥 = 𝐼, 𝑀, if(𝑥 < 𝐼, 𝑥, (𝑥 − 1))))    &   ⊢ 𝐵 = (𝑧 ∈ (1...𝑀) ↦ if(𝑧 = 𝑀, 𝑀, if(𝑧 < 𝐼, (𝑧 + (𝑀 − 𝐼)), (𝑧 + (1 − 𝐼)))))    &   ⊢ (𝜑 → ¬ 𝑋 = 𝐼)    &   ⊢ (𝜑 → 𝑋 < 𝐼)    ⇒   ⊢ (𝜑 → (𝐵‘(𝐴‘𝑋)) = (𝑋 + (𝑀 − 𝐼)))
Theorem	metakunt28 41319*	Construction of one solution of the increment equation system. (Contributed by metakunt, 7-Jul-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ (𝜑 → 𝑋 ∈ (1...𝑀))    &   ⊢ 𝐴 = (𝑥 ∈ (1...𝑀) ↦ if(𝑥 = 𝐼, 𝑀, if(𝑥 < 𝐼, 𝑥, (𝑥 − 1))))    &   ⊢ 𝐵 = (𝑧 ∈ (1...𝑀) ↦ if(𝑧 = 𝑀, 𝑀, if(𝑧 < 𝐼, (𝑧 + (𝑀 − 𝐼)), (𝑧 + (1 − 𝐼)))))    &   ⊢ (𝜑 → ¬ 𝑋 = 𝐼)    &   ⊢ (𝜑 → ¬ 𝑋 < 𝐼)    ⇒   ⊢ (𝜑 → (𝐵‘(𝐴‘𝑋)) = (𝑋 − 𝐼))
Theorem	metakunt29 41320*	Construction of one solution of the increment equation system. (Contributed by metakunt, 7-Jul-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ (𝜑 → 𝑋 ∈ (1...𝑀))    &   ⊢ 𝐴 = (𝑥 ∈ (1...𝑀) ↦ if(𝑥 = 𝐼, 𝑀, if(𝑥 < 𝐼, 𝑥, (𝑥 − 1))))    &   ⊢ 𝐵 = (𝑧 ∈ (1...𝑀) ↦ if(𝑧 = 𝑀, 𝑀, if(𝑧 < 𝐼, (𝑧 + (𝑀 − 𝐼)), (𝑧 + (1 − 𝐼)))))    &   ⊢ (𝜑 → ¬ 𝑋 = 𝐼)    &   ⊢ (𝜑 → 𝑋 < 𝐼)    &   ⊢ 𝐶 = (𝑦 ∈ (1...𝑀) ↦ if(𝑦 = 𝑀, 𝐼, if(𝑦 < 𝐼, 𝑦, (𝑦 + 1))))    &   ⊢ 𝐻 = if(𝐼 ≤ (𝑋 + (𝑀 − 𝐼)), 1, 0)    ⇒   ⊢ (𝜑 → (𝐶‘(𝐵‘(𝐴‘𝑋))) = ((𝑋 + (𝑀 − 𝐼)) + 𝐻))
Theorem	metakunt30 41321*	Construction of one solution of the increment equation system. (Contributed by metakunt, 7-Jul-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ (𝜑 → 𝑋 ∈ (1...𝑀))    &   ⊢ 𝐴 = (𝑥 ∈ (1...𝑀) ↦ if(𝑥 = 𝐼, 𝑀, if(𝑥 < 𝐼, 𝑥, (𝑥 − 1))))    &   ⊢ 𝐵 = (𝑧 ∈ (1...𝑀) ↦ if(𝑧 = 𝑀, 𝑀, if(𝑧 < 𝐼, (𝑧 + (𝑀 − 𝐼)), (𝑧 + (1 − 𝐼)))))    &   ⊢ (𝜑 → ¬ 𝑋 = 𝐼)    &   ⊢ (𝜑 → ¬ 𝑋 < 𝐼)    &   ⊢ 𝐶 = (𝑦 ∈ (1...𝑀) ↦ if(𝑦 = 𝑀, 𝐼, if(𝑦 < 𝐼, 𝑦, (𝑦 + 1))))    &   ⊢ 𝐻 = if(𝐼 ≤ (𝑋 − 𝐼), 1, 0)    ⇒   ⊢ (𝜑 → (𝐶‘(𝐵‘(𝐴‘𝑋))) = ((𝑋 − 𝐼) + 𝐻))
Theorem	metakunt31 41322*	Construction of one solution of the increment equation system. (Contributed by metakunt, 18-Jul-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ (𝜑 → 𝑋 ∈ (1...𝑀))    &   ⊢ 𝐴 = (𝑥 ∈ (1...𝑀) ↦ if(𝑥 = 𝐼, 𝑀, if(𝑥 < 𝐼, 𝑥, (𝑥 − 1))))    &   ⊢ 𝐵 = (𝑧 ∈ (1...𝑀) ↦ if(𝑧 = 𝑀, 𝑀, if(𝑧 < 𝐼, (𝑧 + (𝑀 − 𝐼)), (𝑧 + (1 − 𝐼)))))    &   ⊢ 𝐶 = (𝑦 ∈ (1...𝑀) ↦ if(𝑦 = 𝑀, 𝐼, if(𝑦 < 𝐼, 𝑦, (𝑦 + 1))))    &   ⊢ 𝐺 = if(𝐼 ≤ (𝑋 + (𝑀 − 𝐼)), 1, 0)    &   ⊢ 𝐻 = if(𝐼 ≤ (𝑋 − 𝐼), 1, 0)    &   ⊢ 𝑅 = if(𝑋 = 𝐼, 𝑋, if(𝑋 < 𝐼, ((𝑋 + (𝑀 − 𝐼)) + 𝐺), ((𝑋 − 𝐼) + 𝐻)))    ⇒   ⊢ (𝜑 → (𝐶‘(𝐵‘(𝐴‘𝑋))) = 𝑅)
Theorem	metakunt32 41323*	Construction of one solution of the increment equation system. (Contributed by metakunt, 18-Jul-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ (𝜑 → 𝑋 ∈ (1...𝑀))    &   ⊢ 𝐷 = (𝑥 ∈ (1...𝑀) ↦ if(𝑥 = 𝐼, 𝑥, if(𝑥 < 𝐼, ((𝑥 + (𝑀 − 𝐼)) + if(𝐼 ≤ (𝑥 + (𝑀 − 𝐼)), 1, 0)), ((𝑥 − 𝐼) + if(𝐼 ≤ (𝑥 − 𝐼), 1, 0)))))    &   ⊢ 𝐺 = if(𝐼 ≤ (𝑋 + (𝑀 − 𝐼)), 1, 0)    &   ⊢ 𝐻 = if(𝐼 ≤ (𝑋 − 𝐼), 1, 0)    &   ⊢ 𝑅 = if(𝑋 = 𝐼, 𝑋, if(𝑋 < 𝐼, ((𝑋 + (𝑀 − 𝐼)) + 𝐺), ((𝑋 − 𝐼) + 𝐻)))    ⇒   ⊢ (𝜑 → (𝐷‘𝑋) = 𝑅)
Theorem	metakunt33 41324*	Construction of one solution of the increment equation system. (Contributed by metakunt, 18-Jul-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ 𝐴 = (𝑥 ∈ (1...𝑀) ↦ if(𝑥 = 𝐼, 𝑀, if(𝑥 < 𝐼, 𝑥, (𝑥 − 1))))    &   ⊢ 𝐵 = (𝑧 ∈ (1...𝑀) ↦ if(𝑧 = 𝑀, 𝑀, if(𝑧 < 𝐼, (𝑧 + (𝑀 − 𝐼)), (𝑧 + (1 − 𝐼)))))    &   ⊢ 𝐶 = (𝑦 ∈ (1...𝑀) ↦ if(𝑦 = 𝑀, 𝐼, if(𝑦 < 𝐼, 𝑦, (𝑦 + 1))))    &   ⊢ 𝐷 = (𝑤 ∈ (1...𝑀) ↦ if(𝑤 = 𝐼, 𝑤, if(𝑤 < 𝐼, ((𝑤 + (𝑀 − 𝐼)) + if(𝐼 ≤ (𝑤 + (𝑀 − 𝐼)), 1, 0)), ((𝑤 − 𝐼) + if(𝐼 ≤ (𝑤 − 𝐼), 1, 0)))))    ⇒   ⊢ (𝜑 → (𝐶 ∘ (𝐵 ∘ 𝐴)) = 𝐷)
Theorem	metakunt34 41325*	𝐷 is a permutation. (Contributed by metakunt, 18-Jul-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ∈ ℕ)    &   ⊢ (𝜑 → 𝐼 ≤ 𝑀)    &   ⊢ 𝐷 = (𝑤 ∈ (1...𝑀) ↦ if(𝑤 = 𝐼, 𝑤, if(𝑤 < 𝐼, ((𝑤 + (𝑀 − 𝐼)) + if(𝐼 ≤ (𝑤 + (𝑀 − 𝐼)), 1, 0)), ((𝑤 − 𝐼) + if(𝐼 ≤ (𝑤 − 𝐼), 1, 0)))))    ⇒   ⊢ (𝜑 → 𝐷:(1...𝑀)–1-1-onto→(1...𝑀))
21.27.9  Unused lemmas scheduled for deletion
Theorem	andiff 41326	Adding biconditional when antecedents are conjuncted. (Contributed by metakunt, 16-Apr-2024.)
⊢ (𝜑 → (𝜒 → 𝜃))    &   ⊢ (𝜓 → (𝜃 → 𝜒))    ⇒   ⊢ ((𝜑 ∧ 𝜓) → (𝜒 ↔ 𝜃))
Theorem	fac2xp3 41327	Factorial of 2x+3, sublemma for sublemma for AKS. (Contributed by metakunt, 19-Apr-2024.)
⊢ (𝑥 ∈ ℕ0 → (!‘((2 · 𝑥) + 3)) = ((!‘((2 · 𝑥) + 1)) · (((2 · 𝑥) + 2) · ((2 · 𝑥) + 3))))
Theorem	prodsplit 41328*	Product split into two factors, original by Steven Nguyen. (Contributed by metakunt, 21-Apr-2024.)
⊢ (𝜑 → 𝑀 ∈ ℤ)    &   ⊢ (𝜑 → 𝑁 ∈ ℤ)    &   ⊢ (𝜑 → 𝑀 ≤ 𝑁)    &   ⊢ (𝜑 → 𝐾 ∈ ℕ0)    &   ⊢ ((𝜑 ∧ 𝑘 ∈ (𝑀...(𝑁 + 𝐾))) → 𝐴 ∈ ℂ)    ⇒   ⊢ (𝜑 → ∏𝑘 ∈ (𝑀...(𝑁 + 𝐾))𝐴 = (∏𝑘 ∈ (𝑀...𝑁)𝐴 · ∏𝑘 ∈ ((𝑁 + 1)...(𝑁 + 𝐾))𝐴))
Theorem	2xp3dxp2ge1d 41329	2x+3 is greater than or equal to x+2 for x >= -1, a deduction version (Contributed by metakunt, 21-Apr-2024.)
⊢ (𝜑 → 𝑋 ∈ (-1[,)+∞))    ⇒   ⊢ (𝜑 → 1 ≤ (((2 · 𝑋) + 3) / (𝑋 + 2)))
Theorem	factwoffsmonot 41330	A factorial with offset is monotonely increasing. (Contributed by metakunt, 20-Apr-2024.)
⊢ (((𝑋 ∈ ℕ0 ∧ 𝑌 ∈ ℕ0 ∧ 𝑋 ≤ 𝑌) ∧ 𝑁 ∈ ℕ0) → (!‘(𝑋 + 𝑁)) ≤ (!‘(𝑌 + 𝑁)))
21.28  Mathbox for Steven Nguyen
21.28.1  Utility theorems
Theorem	ioin9i8 41331	Miscellaneous inference creating a biconditional from an implied converse implication. (Contributed by Steven Nguyen, 17-Jul-2022.)
⊢ (𝜑 → (𝜓 ∨ 𝜒))    &   ⊢ (𝜒 → ¬ 𝜃)    &   ⊢ (𝜓 → 𝜃)    ⇒   ⊢ (𝜑 → (𝜓 ↔ 𝜃))
Theorem	jaodd 41332	Double deduction form of jaoi 854. (Contributed by Steven Nguyen, 17-Jul-2022.)
⊢ (𝜑 → (𝜓 → (𝜒 → 𝜃)))    &   ⊢ (𝜑 → (𝜓 → (𝜏 → 𝜃)))    ⇒   ⊢ (𝜑 → (𝜓 → ((𝜒 ∨ 𝜏) → 𝜃)))
Theorem	syl3an12 41333	A double syllogism inference. (Contributed by SN, 15-Sep-2024.)
⊢ (𝜑 → 𝜓)    &   ⊢ (𝜒 → 𝜃)    &   ⊢ ((𝜓 ∧ 𝜃 ∧ 𝜏) → 𝜂)    ⇒   ⊢ ((𝜑 ∧ 𝜒 ∧ 𝜏) → 𝜂)
Theorem	sbtd 41334*	A true statement is true upon substitution (deduction). A similar proof is possible for icht 46419. (Contributed by SN, 4-May-2024.)
⊢ (𝜑 → 𝜓)    ⇒   ⊢ (𝜑 → [𝑡 / 𝑥]𝜓)
Theorem	sbor2 41335	One direction of sbor 2302, using fewer axioms. Compare 19.33 1886. (Contributed by Steven Nguyen, 18-Aug-2023.)
⊢ (([𝑡 / 𝑥]𝜑 ∨ [𝑡 / 𝑥]𝜓) → [𝑡 / 𝑥](𝜑 ∨ 𝜓))
Theorem	19.9dev 41336*	19.9d 2195 in the case of an existential quantifier, avoiding the ax-10 2136 from nfex 2316 that would be used for the hypothesis of 19.9d 2195, at the cost of an additional DV condition on 𝑦, 𝜑. (Contributed by SN, 26-May-2024.)
⊢ (𝜑 → Ⅎ𝑥𝜓)    ⇒   ⊢ (𝜑 → (∃𝑥∃𝑦𝜓 ↔ ∃𝑦𝜓))
Theorem	3rspcedvdw 41337*	Triple application of rspcedvdw 3615. (Contributed by SN, 20-Aug-2024.)
⊢ (𝑥 = 𝐴 → (𝜓 ↔ 𝜒))    &   ⊢ (𝑦 = 𝐵 → (𝜒 ↔ 𝜃))    &   ⊢ (𝑧 = 𝐶 → (𝜃 ↔ 𝜏))    &   ⊢ (𝜑 → 𝐴 ∈ 𝑋)    &   ⊢ (𝜑 → 𝐵 ∈ 𝑌)    &   ⊢ (𝜑 → 𝐶 ∈ 𝑍)    &   ⊢ (𝜑 → 𝜏)    ⇒   ⊢ (𝜑 → ∃𝑥 ∈ 𝑋 ∃𝑦 ∈ 𝑌 ∃𝑧 ∈ 𝑍 𝜓)
Theorem	3rspcedvd 41338*	Triple application of rspcedvd 3614. (Contributed by Steven Nguyen, 27-Feb-2023.)
⊢ (𝜑 → 𝐴 ∈ 𝐷)    &   ⊢ (𝜑 → 𝐵 ∈ 𝐷)    &   ⊢ (𝜑 → 𝐶 ∈ 𝐷)    &   ⊢ ((𝜑 ∧ 𝑥 = 𝐴) → (𝜓 ↔ 𝜒))    &   ⊢ ((𝜑 ∧ 𝑦 = 𝐵) → (𝜒 ↔ 𝜃))    &   ⊢ ((𝜑 ∧ 𝑧 = 𝐶) → (𝜃 ↔ 𝜏))    &   ⊢ (𝜑 → 𝜏)    ⇒   ⊢ (𝜑 → ∃𝑥 ∈ 𝐷 ∃𝑦 ∈ 𝐷 ∃𝑧 ∈ 𝐷 𝜓)
Theorem	rabdif 41339*	Move difference in and out of a restricted class abstraction. (Contributed by Steven Nguyen, 6-Jun-2023.)
⊢ ({𝑥 ∈ 𝐴 ∣ 𝜑} ∖ 𝐵) = {𝑥 ∈ (𝐴 ∖ 𝐵) ∣ 𝜑}
Theorem	sn-axrep5v 41340*	A condensed form of axrep5 5291. (Contributed by SN, 21-Sep-2023.)
⊢ (∀𝑤 ∈ 𝑥 ∃*𝑧𝜑 → ∃𝑦∀𝑧(𝑧 ∈ 𝑦 ↔ ∃𝑤 ∈ 𝑥 𝜑))
Theorem	sn-axprlem3 41341*	axprlem3 5423 using only Tarski's FOL axiom schemes and ax-rep 5285. (Contributed by SN, 22-Sep-2023.)
⊢ ∃𝑦∀𝑧(𝑧 ∈ 𝑦 ↔ ∃𝑤 ∈ 𝑥 if-(𝜑, 𝑧 = 𝑎, 𝑧 = 𝑏))
Theorem	sn-exelALT 41342*	Alternate proof of exel 5433, avoiding ax-pr 5427 but requiring ax-5 1912, ax-9 2115, and ax-pow 5363. This is similar to how elALT2 5367 uses ax-pow 5363 instead of ax-pr 5427 compared to el 5437. (Contributed by SN, 18-Sep-2023.) (Proof modification is discouraged.) (New usage is discouraged.)
⊢ ∃𝑦∃𝑥 𝑥 ∈ 𝑦
Theorem	ss2ab1 41343	Class abstractions in a subclass relationship, closed form. One direction of ss2ab 4056 using fewer axioms. (Contributed by SN, 22-Dec-2024.)
⊢ (∀𝑥(𝜑 → 𝜓) → {𝑥 ∣ 𝜑} ⊆ {𝑥 ∣ 𝜓})
Theorem	ssabdv 41344*	Deduction of abstraction subclass from implication. (Contributed by SN, 22-Dec-2024.)
⊢ (𝜑 → (𝑥 ∈ 𝐴 → 𝜓))    ⇒   ⊢ (𝜑 → 𝐴 ⊆ {𝑥 ∣ 𝜓})
Theorem	sn-iotalem 41345*	An unused lemma showing that many equivalences involving df-iota 6495 are potentially provable without ax-10 2136, ax-11 2153, ax-12 2170. (Contributed by SN, 6-Nov-2024.)
⊢ {𝑦 ∣ {𝑥 ∣ 𝜑} = {𝑦}} = {𝑧 ∣ {𝑦 ∣ {𝑥 ∣ 𝜑} = {𝑦}} = {𝑧}}
Theorem	sn-iotalemcor 41346*	Corollary of sn-iotalem 41345. Compare sb8iota 6507. (Contributed by SN, 6-Nov-2024.)
⊢ (℩𝑥𝜑) = (℩𝑦{𝑥 ∣ 𝜑} = {𝑦})
Theorem	abbi1sn 41347*	Originally part of uniabio 6510. Convert a theorem about df-iota 6495 to one about dfiota2 6496, without ax-10 2136, ax-11 2153, ax-12 2170. Although, eu6 2567 uses ax-10 2136 and ax-12 2170. (Contributed by SN, 23-Nov-2024.)
⊢ (∀𝑥(𝜑 ↔ 𝑥 = 𝑦) → {𝑥 ∣ 𝜑} = {𝑦})
Theorem	brif1 41348	Move a relation inside and outside the conditional operator. (Contributed by SN, 14-Aug-2024.)
⊢ (if(𝜑, 𝐴, 𝐵)𝑅𝐶 ↔ if-(𝜑, 𝐴𝑅𝐶, 𝐵𝑅𝐶))
Theorem	brif2 41349	Move a relation inside and outside the conditional operator. (Contributed by SN, 14-Aug-2024.)
⊢ (𝐶𝑅if(𝜑, 𝐴, 𝐵) ↔ if-(𝜑, 𝐶𝑅𝐴, 𝐶𝑅𝐵))
Theorem	brif12 41350	Move a relation inside and outside the conditional operator. (Contributed by SN, 14-Aug-2024.)
⊢ (if(𝜑, 𝐴, 𝐵)𝑅if(𝜑, 𝐶, 𝐷) ↔ if-(𝜑, 𝐴𝑅𝐶, 𝐵𝑅𝐷))
Theorem	pssexg 41351	The proper subset of a set is also a set. (Contributed by Steven Nguyen, 17-Jul-2022.)
⊢ ((𝐴 ⊊ 𝐵 ∧ 𝐵 ∈ 𝐶) → 𝐴 ∈ V)
Theorem	pssn0 41352	A proper superset is nonempty. (Contributed by Steven Nguyen, 17-Jul-2022.)
⊢ (𝐴 ⊊ 𝐵 → 𝐵 ≠ ∅)
Theorem	psspwb 41353	Classes are proper subclasses if and only if their power classes are proper subclasses. (Contributed by Steven Nguyen, 17-Jul-2022.)
⊢ (𝐴 ⊊ 𝐵 ↔ 𝒫 𝐴 ⊊ 𝒫 𝐵)
Theorem	xppss12 41354	Proper subset theorem for Cartesian product. (Contributed by Steven Nguyen, 17-Jul-2022.)
⊢ ((𝐴 ⊊ 𝐵 ∧ 𝐶 ⊊ 𝐷) → (𝐴 × 𝐶) ⊊ (𝐵 × 𝐷))
Theorem	coexd 41355	The composition of two sets is a set. (Contributed by SN, 7-Feb-2025.)
⊢ (𝜑 → 𝐴 ∈ 𝑉)    &   ⊢ (𝜑 → 𝐵 ∈ 𝑊)    ⇒   ⊢ (𝜑 → (𝐴 ∘ 𝐵) ∈ V)
Theorem	elpwbi 41356	Membership in a power set, biconditional. (Contributed by Steven Nguyen, 17-Jul-2022.) (Proof shortened by Steven Nguyen, 16-Sep-2022.)
⊢ 𝐵 ∈ V    ⇒   ⊢ (𝐴 ⊆ 𝐵 ↔ 𝐴 ∈ 𝒫 𝐵)
Theorem	imaopab 41357*	The image of a class of ordered pairs. (Contributed by Steven Nguyen, 6-Jun-2023.)
⊢ ({⟨𝑥, 𝑦⟩ ∣ 𝜑} “ 𝐴) = {𝑦 ∣ ∃𝑥 ∈ 𝐴 𝜑}
Theorem	fnsnbt 41358	A function's domain is a singleton iff the function is a singleton. (Contributed by Steven Nguyen, 18-Aug-2023.)
⊢ (𝐴 ∈ V → (𝐹 Fn {𝐴} ↔ 𝐹 = {⟨𝐴, (𝐹‘𝐴)⟩}))
Theorem	fnimasnd 41359	The image of a function by a singleton whose element is in the domain of the function. (Contributed by Steven Nguyen, 7-Jun-2023.)
⊢ (𝜑 → 𝐹 Fn 𝐴)    &   ⊢ (𝜑 → 𝑆 ∈ 𝐴)    ⇒   ⊢ (𝜑 → (𝐹 “ {𝑆}) = {(𝐹‘𝑆)})
Theorem	fvmptd4 41360*	Deduction version of fvmpt 6998 (where the substitution hypothesis does not have the antecedent 𝜑). (Contributed by SN, 26-Jul-2024.)
⊢ (𝑥 = 𝐴 → 𝐵 = 𝐶)    &   ⊢ (𝜑 → 𝐹 = (𝑥 ∈ 𝐷 ↦ 𝐵))    &   ⊢ (𝜑 → 𝐴 ∈ 𝐷)    &   ⊢ (𝜑 → 𝐶 ∈ 𝑉)    ⇒   ⊢ (𝜑 → (𝐹‘𝐴) = 𝐶)
Theorem	eqresfnbd 41361	Property of being the restriction of a function. Note that this is closer to funssres 6592 than fnssres 6673. (Contributed by SN, 11-Mar-2025.)
⊢ (𝜑 → 𝐹 Fn 𝐵)    &   ⊢ (𝜑 → 𝐴 ⊆ 𝐵)    ⇒   ⊢ (𝜑 → (𝑅 = (𝐹 ↾ 𝐴) ↔ (𝑅 Fn 𝐴 ∧ 𝑅 ⊆ 𝐹)))
Theorem	f1o2d2 41362*	Sufficient condition for a binary function expressed in maps-to notation to be bijective. (Contributed by SN, 11-Mar-2025.)
⊢ 𝐹 = (𝑥 ∈ 𝐴, 𝑦 ∈ 𝐵 ↦ 𝐶)    &   ⊢ ((𝜑 ∧ (𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵)) → 𝐶 ∈ 𝐷)    &   ⊢ ((𝜑 ∧ 𝑧 ∈ 𝐷) → 𝐼 ∈ 𝐴)    &   ⊢ ((𝜑 ∧ 𝑧 ∈ 𝐷) → 𝐽 ∈ 𝐵)    &   ⊢ ((𝜑 ∧ ((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) ∧ 𝑧 ∈ 𝐷)) → ((𝑥 = 𝐼 ∧ 𝑦 = 𝐽) ↔ 𝑧 = 𝐶))    ⇒   ⊢ (𝜑 → 𝐹:(𝐴 × 𝐵)–1-1-onto→𝐷)
Theorem	fmpocos 41363*	Composition of two functions. Variation of fmpoco 8085 with more context in the substitution hypothesis for 𝑇. (Contributed by SN, 14-Mar-2025.)
⊢ ((𝜑 ∧ (𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵)) → 𝑅 ∈ 𝐶)    &   ⊢ (𝜑 → 𝐹 = (𝑥 ∈ 𝐴, 𝑦 ∈ 𝐵 ↦ 𝑅))    &   ⊢ (𝜑 → 𝐺 = (𝑧 ∈ 𝐶 ↦ 𝑆))    &   ⊢ ((𝜑 ∧ (𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵)) → ⦋𝑅 / 𝑧⦌𝑆 = 𝑇)    ⇒   ⊢ (𝜑 → (𝐺 ∘ 𝐹) = (𝑥 ∈ 𝐴, 𝑦 ∈ 𝐵 ↦ 𝑇))
Theorem	ovmpogad 41364*	Value of an operation given by a maps-to rule. Deduction form of ovmpoga 7565. (Contributed by SN, 14-Mar-2025.)
⊢ 𝐹 = (𝑥 ∈ 𝐶, 𝑦 ∈ 𝐷 ↦ 𝑅)    &   ⊢ ((𝑥 = 𝐴 ∧ 𝑦 = 𝐵) → 𝑅 = 𝑆)    &   ⊢ (𝜑 → 𝐴 ∈ 𝐶)    &   ⊢ (𝜑 → 𝐵 ∈ 𝐷)    &   ⊢ (𝜑 → 𝑆 ∈ 𝑉)    ⇒   ⊢ (𝜑 → (𝐴𝐹𝐵) = 𝑆)
Theorem	ofun 41365	A function operation of unions of disjoint functions is a union of function operations. (Contributed by SN, 16-Jun-2024.)
⊢ (𝜑 → 𝐴 Fn 𝑀)    &   ⊢ (𝜑 → 𝐵 Fn 𝑀)    &   ⊢ (𝜑 → 𝐶 Fn 𝑁)    &   ⊢ (𝜑 → 𝐷 Fn 𝑁)    &   ⊢ (𝜑 → 𝑀 ∈ 𝑉)    &   ⊢ (𝜑 → 𝑁 ∈ 𝑊)    &   ⊢ (𝜑 → (𝑀 ∩ 𝑁) = ∅)    ⇒   ⊢ (𝜑 → ((𝐴 ∪ 𝐶) ∘f 𝑅(𝐵 ∪ 𝐷)) = ((𝐴 ∘f 𝑅𝐵) ∪ (𝐶 ∘f 𝑅𝐷)))
Theorem	dfqs2 41366*	Alternate definition of quotient set. (Contributed by Steven Nguyen, 7-Jun-2023.)
⊢ (𝐴 / 𝑅) = ran (𝑥 ∈ 𝐴 ↦ [𝑥]𝑅)
Theorem	dfqs3 41367*	Alternate definition of quotient set. (Contributed by Steven Nguyen, 7-Jun-2023.)
⊢ (𝐴 / 𝑅) = ∪ 𝑥 ∈ 𝐴 {[𝑥]𝑅}
Theorem	qseq12d 41368	Equality theorem for quotient set, deduction form. (Contributed by Steven Nguyen, 30-Apr-2023.)
⊢ (𝜑 → 𝐴 = 𝐵)    &   ⊢ (𝜑 → 𝐶 = 𝐷)    ⇒   ⊢ (𝜑 → (𝐴 / 𝐶) = (𝐵 / 𝐷))
Theorem	qsalrel 41369*	The quotient set is equal to the singleton of 𝐴 when all elements are related and 𝐴 is nonempty. (Contributed by SN, 8-Jun-2023.)
⊢ ((𝜑 ∧ (𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐴)) → 𝑥 ∼ 𝑦)    &   ⊢ (𝜑 → ∼ Er 𝐴)    &   ⊢ (𝜑 → 𝑁 ∈ 𝐴)    ⇒   ⊢ (𝜑 → (𝐴 / ∼ ) = {𝐴})
Theorem	fsuppfund 41370	A finitely supported function is a function. (Contributed by SN, 8-Mar-2025.)
⊢ (𝜑 → 𝐹 finSupp 𝑍)    ⇒   ⊢ (𝜑 → Fun 𝐹)
Theorem	fsuppsssuppgd 41371	If the support of a function is a subset of a finite support, it is finite. Deduction associated with fsuppsssupp 9383. (Contributed by SN, 6-Mar-2025.)
⊢ (𝜑 → 𝐺 ∈ 𝑉)    &   ⊢ (𝜑 → 𝑍 ∈ 𝑊)    &   ⊢ (𝜑 → Fun 𝐺)    &   ⊢ (𝜑 → 𝐹 finSupp 𝑂)    &   ⊢ (𝜑 → (𝐺 supp 𝑍) ⊆ (𝐹 supp 𝑂))    ⇒   ⊢ (𝜑 → 𝐺 finSupp 𝑍)
Theorem	fsuppss 41372	A subset of a finitely supported function is a finitely supported function. (Contributed by SN, 8-Mar-2025.)
⊢ (𝜑 → 𝐹 ⊆ 𝐺)    &   ⊢ (𝜑 → 𝐺 finSupp 𝑍)    ⇒   ⊢ (𝜑 → 𝐹 finSupp 𝑍)
Theorem	elmapssresd 41373	A restricted mapping is a mapping. EDITORIAL: Could be used to shorten elpm2r 8843 with some reordering involving mapsspm 8874. (Contributed by SN, 11-Mar-2025.)
⊢ (𝜑 → 𝐴 ∈ (𝐵 ↑m 𝐶))    &   ⊢ (𝜑 → 𝐷 ⊆ 𝐶)    ⇒   ⊢ (𝜑 → (𝐴 ↾ 𝐷) ∈ (𝐵 ↑m 𝐷))
Theorem	mapcod 41374	Compose two mappings. (Contributed by SN, 11-Mar-2025.)
⊢ (𝜑 → 𝐹 ∈ (𝐴 ↑m 𝐵))    &   ⊢ (𝜑 → 𝐺 ∈ (𝐵 ↑m 𝐶))    ⇒   ⊢ (𝜑 → (𝐹 ∘ 𝐺) ∈ (𝐴 ↑m 𝐶))
Theorem	fzosumm1 41375*	Separate out the last term in a finite sum. (Contributed by Steven Nguyen, 22-Aug-2023.)
⊢ (𝜑 → (𝑁 − 1) ∈ (ℤ≥‘𝑀))    &   ⊢ ((𝜑 ∧ 𝑘 ∈ (𝑀..^𝑁)) → 𝐴 ∈ ℂ)    &   ⊢ (𝑘 = (𝑁 − 1) → 𝐴 = 𝐵)    &   ⊢ (𝜑 → 𝑁 ∈ ℤ)    ⇒   ⊢ (𝜑 → Σ𝑘 ∈ (𝑀..^𝑁)𝐴 = (Σ𝑘 ∈ (𝑀..^(𝑁 − 1))𝐴 + 𝐵))
Theorem	ccatcan2d 41376	Cancellation law for concatenation. (Contributed by SN, 6-Sep-2023.)
⊢ (𝜑 → 𝐴 ∈ Word 𝑉)    &   ⊢ (𝜑 → 𝐵 ∈ Word 𝑉)    &   ⊢ (𝜑 → 𝐶 ∈ Word 𝑉)    ⇒   ⊢ (𝜑 → ((𝐴 ++ 𝐶) = (𝐵 ++ 𝐶) ↔ 𝐴 = 𝐵))
21.28.2  Structures
Theorem	nelsubginvcld 41377	The inverse of a non-subgroup-member is a non-subgroup-member. (Contributed by Steven Nguyen, 15-Apr-2023.)
⊢ (𝜑 → 𝐺 ∈ Grp)    &   ⊢ (𝜑 → 𝑆 ∈ (SubGrp‘𝐺))    &   ⊢ (𝜑 → 𝑋 ∈ (𝐵 ∖ 𝑆))    &   ⊢ 𝐵 = (Base‘𝐺)    &   ⊢ 𝑁 = (invg‘𝐺)    ⇒   ⊢ (𝜑 → (𝑁‘𝑋) ∈ (𝐵 ∖ 𝑆))
Theorem	nelsubgcld 41378	A non-subgroup-member plus a subgroup member is a non-subgroup-member. (Contributed by Steven Nguyen, 15-Apr-2023.)
⊢ (𝜑 → 𝐺 ∈ Grp)    &   ⊢ (𝜑 → 𝑆 ∈ (SubGrp‘𝐺))    &   ⊢ (𝜑 → 𝑋 ∈ (𝐵 ∖ 𝑆))    &   ⊢ 𝐵 = (Base‘𝐺)    &   ⊢ (𝜑 → 𝑌 ∈ 𝑆)    &   ⊢ + = (+g‘𝐺)    ⇒   ⊢ (𝜑 → (𝑋 + 𝑌) ∈ (𝐵 ∖ 𝑆))
Theorem	nelsubgsubcld 41379	A non-subgroup-member minus a subgroup member is a non-subgroup-member. (Contributed by Steven Nguyen, 15-Apr-2023.)
⊢ (𝜑 → 𝐺 ∈ Grp)    &   ⊢ (𝜑 → 𝑆 ∈ (SubGrp‘𝐺))    &   ⊢ (𝜑 → 𝑋 ∈ (𝐵 ∖ 𝑆))    &   ⊢ 𝐵 = (Base‘𝐺)    &   ⊢ (𝜑 → 𝑌 ∈ 𝑆)    &   ⊢ − = (-g‘𝐺)    ⇒   ⊢ (𝜑 → (𝑋 − 𝑌) ∈ (𝐵 ∖ 𝑆))
Theorem	rnasclg 41380	The set of injected scalars is also interpretable as the span of the identity. (Contributed by Mario Carneiro, 9-Mar-2015.)
⊢ 𝐴 = (algSc‘𝑊)    &   ⊢ 1 = (1r‘𝑊)    &   ⊢ 𝑁 = (LSpan‘𝑊)    ⇒   ⊢ ((𝑊 ∈ LMod ∧ 𝑊 ∈ Ring) → ran 𝐴 = (𝑁‘{ 1 }))
Theorem	frlmfielbas 41381	The vectors of a finite free module are the functions from 𝐼 to 𝑁. (Contributed by SN, 31-Aug-2023.)
⊢ 𝐹 = (𝑅 freeLMod 𝐼)    &   ⊢ 𝑁 = (Base‘𝑅)    &   ⊢ 𝐵 = (Base‘𝐹)    ⇒   ⊢ ((𝑅 ∈ 𝑉 ∧ 𝐼 ∈ Fin) → (𝑋 ∈ 𝐵 ↔ 𝑋:𝐼⟶𝑁))
Theorem	frlmfzwrd 41382	A vector of a module with indices from 0 to 𝑁 is a word over the scalars of the module. (Contributed by SN, 31-Aug-2023.)
⊢ 𝑊 = (𝐾 freeLMod (0...𝑁))    &   ⊢ 𝐵 = (Base‘𝑊)    &   ⊢ 𝑆 = (Base‘𝐾)    ⇒   ⊢ (𝑋 ∈ 𝐵 → 𝑋 ∈ Word 𝑆)
Theorem	frlmfzowrd 41383	A vector of a module with indices from 0 to 𝑁 − 1 is a word over the scalars of the module. (Contributed by SN, 31-Aug-2023.)
⊢ 𝑊 = (𝐾 freeLMod (0..^𝑁))    &   ⊢ 𝐵 = (Base‘𝑊)    &   ⊢ 𝑆 = (Base‘𝐾)    ⇒   ⊢ (𝑋 ∈ 𝐵 → 𝑋 ∈ Word 𝑆)
Theorem	frlmfzolen 41384	The dimension of a vector of a module with indices from 0 to 𝑁 − 1. (Contributed by SN, 1-Sep-2023.)
⊢ 𝑊 = (𝐾 freeLMod (0..^𝑁))    &   ⊢ 𝐵 = (Base‘𝑊)    &   ⊢ 𝑆 = (Base‘𝐾)    ⇒   ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑋 ∈ 𝐵) → (♯‘𝑋) = 𝑁)
Theorem	frlmfzowrdb 41385	The vectors of a module with indices 0 to 𝑁 − 1 are the length- 𝑁 words over the scalars of the module. (Contributed by SN, 1-Sep-2023.)
⊢ 𝑊 = (𝐾 freeLMod (0..^𝑁))    &   ⊢ 𝐵 = (Base‘𝑊)    &   ⊢ 𝑆 = (Base‘𝐾)    ⇒   ⊢ ((𝐾 ∈ 𝑉 ∧ 𝑁 ∈ ℕ0) → (𝑋 ∈ 𝐵 ↔ (𝑋 ∈ Word 𝑆 ∧ (♯‘𝑋) = 𝑁)))
Theorem	frlmfzoccat 41386	The concatenation of two vectors of dimension 𝑁 and 𝑀 forms a vector of dimension 𝑁 + 𝑀. (Contributed by SN, 31-Aug-2023.)
⊢ 𝑊 = (𝐾 freeLMod (0..^𝐿))    &   ⊢ 𝑋 = (𝐾 freeLMod (0..^𝑀))    &   ⊢ 𝑌 = (𝐾 freeLMod (0..^𝑁))    &   ⊢ 𝐵 = (Base‘𝑊)    &   ⊢ 𝐶 = (Base‘𝑋)    &   ⊢ 𝐷 = (Base‘𝑌)    &   ⊢ (𝜑 → 𝐾 ∈ 𝑍)    &   ⊢ (𝜑 → (𝑀 + 𝑁) = 𝐿)    &   ⊢ (𝜑 → 𝑀 ∈ ℕ0)    &   ⊢ (𝜑 → 𝑁 ∈ ℕ0)    &   ⊢ (𝜑 → 𝑈 ∈ 𝐶)    &   ⊢ (𝜑 → 𝑉 ∈ 𝐷)    ⇒   ⊢ (𝜑 → (𝑈 ++ 𝑉) ∈ 𝐵)
Theorem	frlmvscadiccat 41387	Scalar multiplication distributes over concatenation. (Contributed by SN, 6-Sep-2023.)
⊢ 𝑊 = (𝐾 freeLMod (0..^𝐿))    &   ⊢ 𝑋 = (𝐾 freeLMod (0..^𝑀))    &   ⊢ 𝑌 = (𝐾 freeLMod (0..^𝑁))    &   ⊢ 𝐵 = (Base‘𝑊)    &   ⊢ 𝐶 = (Base‘𝑋)    &   ⊢ 𝐷 = (Base‘𝑌)    &   ⊢ (𝜑 → 𝐾 ∈ 𝑍)    &   ⊢ (𝜑 → (𝑀 + 𝑁) = 𝐿)    &   ⊢ (𝜑 → 𝑀 ∈ ℕ0)    &   ⊢ (𝜑 → 𝑁 ∈ ℕ0)    &   ⊢ (𝜑 → 𝑈 ∈ 𝐶)    &   ⊢ (𝜑 → 𝑉 ∈ 𝐷)    &   ⊢ 𝑂 = ( ·𝑠 ‘𝑊)    &   ⊢ ∙ = ( ·𝑠 ‘𝑋)    &   ⊢ · = ( ·𝑠 ‘𝑌)    &   ⊢ 𝑆 = (Base‘𝐾)    &   ⊢ (𝜑 → 𝐴 ∈ 𝑆)    ⇒   ⊢ (𝜑 → (𝐴𝑂(𝑈 ++ 𝑉)) = ((𝐴 ∙ 𝑈) ++ (𝐴 · 𝑉)))
Theorem	grpasscan2d 41388	An associative cancellation law for groups. (Contributed by SN, 29-Jan-2025.)
⊢ 𝐵 = (Base‘𝐺)    &   ⊢ + = (+g‘𝐺)    &   ⊢ 𝑁 = (invg‘𝐺)    &   ⊢ (𝜑 → 𝐺 ∈ Grp)    &   ⊢ (𝜑 → 𝑋 ∈ 𝐵)    &   ⊢ (𝜑 → 𝑌 ∈ 𝐵)    ⇒   ⊢ (𝜑 → ((𝑋 + (𝑁‘𝑌)) + 𝑌) = 𝑋)
Theorem	grpcominv1 41389	If two elements commute, then they commute with each other's inverses (case of the first element commuting with the inverse of the second element). (Contributed by SN, 29-Jan-2025.)
⊢ 𝐵 = (Base‘𝐺)    &   ⊢ + = (+g‘𝐺)    &   ⊢ 𝑁 = (invg‘𝐺)    &   ⊢ (𝜑 → 𝐺 ∈ Grp)    &   ⊢ (𝜑 → 𝑋 ∈ 𝐵)    &   ⊢ (𝜑 → 𝑌 ∈ 𝐵)    &   ⊢ (𝜑 → (𝑋 + 𝑌) = (𝑌 + 𝑋))    ⇒   ⊢ (𝜑 → (𝑋 + (𝑁‘𝑌)) = ((𝑁‘𝑌) + 𝑋))
Theorem	grpcominv2 41390	If two elements commute, then they commute with each other's inverses (case of the second element commuting with the inverse of the first element). (Contributed by SN, 1-Feb-2025.)
⊢ 𝐵 = (Base‘𝐺)    &   ⊢ + = (+g‘𝐺)    &   ⊢ 𝑁 = (invg‘𝐺)    &   ⊢ (𝜑 → 𝐺 ∈ Grp)    &   ⊢ (𝜑 → 𝑋 ∈ 𝐵)    &   ⊢ (𝜑 → 𝑌 ∈ 𝐵)    &   ⊢ (𝜑 → (𝑋 + 𝑌) = (𝑌 + 𝑋))    ⇒   ⊢ (𝜑 → (𝑌 + (𝑁‘𝑋)) = ((𝑁‘𝑋) + 𝑌))
Theorem	finsubmsubg 41391	A submonoid of a finite group is a subgroup. This does not extend to infinite groups, as the submonoid ℕ0 of the group (ℤ, + ) shows. Note also that the union of a submonoid and its inverses need not be a submonoid, as the submonoid (ℕ0 ∖ {1}) of the group (ℤ, + ) shows: 3 is in that submonoid, -2 is the inverse of 2, but 1 is not in their union. Or simply, the subgroup generated by (ℕ0 ∖ {1}) is ℤ, not (ℤ ∖ {1, -1}). (Contributed by SN, 31-Jan-2025.)
⊢ 𝐵 = (Base‘𝐺)    &   ⊢ (𝜑 → 𝐺 ∈ Grp)    &   ⊢ (𝜑 → 𝑆 ∈ (SubMnd‘𝐺))    &   ⊢ (𝜑 → 𝐵 ∈ Fin)    ⇒   ⊢ (𝜑 → 𝑆 ∈ (SubGrp‘𝐺))
Theorem	crngcomd 41392	Multiplication is commutative in a commutative ring. (Contributed by SN, 8-Mar-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ · = (.r‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ CRing)    &   ⊢ (𝜑 → 𝑋 ∈ 𝐵)    &   ⊢ (𝜑 → 𝑌 ∈ 𝐵)    ⇒   ⊢ (𝜑 → (𝑋 · 𝑌) = (𝑌 · 𝑋))
Theorem	crng12d 41393	Commutative/associative law that swaps the first two factors in a triple product. (Contributed by SN, 8-Mar-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ · = (.r‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ CRing)    &   ⊢ (𝜑 → 𝑋 ∈ 𝐵)    &   ⊢ (𝜑 → 𝑌 ∈ 𝐵)    &   ⊢ (𝜑 → 𝑍 ∈ 𝐵)    ⇒   ⊢ (𝜑 → (𝑋 · (𝑌 · 𝑍)) = (𝑌 · (𝑋 · 𝑍)))
Theorem	imacrhmcl 41394	The image of a commutative ring homomorphism is a commutative ring. (Contributed by SN, 10-Jan-2025.)
⊢ 𝐶 = (𝑁 ↾s (𝐹 “ 𝑆))    &   ⊢ (𝜑 → 𝐹 ∈ (𝑀 RingHom 𝑁))    &   ⊢ (𝜑 → 𝑀 ∈ CRing)    &   ⊢ (𝜑 → 𝑆 ∈ (SubRing‘𝑀))    ⇒   ⊢ (𝜑 → 𝐶 ∈ CRing)
Theorem	rimrcl1 41395	Reverse closure of a ring isomorphism. (Contributed by SN, 19-Feb-2025.)
⊢ (𝐹 ∈ (𝑅 RingIso 𝑆) → 𝑅 ∈ Ring)
Theorem	rimrcl2 41396	Reverse closure of a ring isomorphism. (Contributed by SN, 19-Feb-2025.)
⊢ (𝐹 ∈ (𝑅 RingIso 𝑆) → 𝑆 ∈ Ring)
Theorem	rimcnv 41397	The converse of a ring isomorphism is a ring isomorphism. (Contributed by SN, 10-Jan-2025.)
⊢ (𝐹 ∈ (𝑅 RingIso 𝑆) → ◡𝐹 ∈ (𝑆 RingIso 𝑅))
Theorem	rimco 41398	The composition of ring isomorphisms is a ring isomorphism. (Contributed by SN, 17-Jan-2025.)
⊢ ((𝐹 ∈ (𝑆 RingIso 𝑇) ∧ 𝐺 ∈ (𝑅 RingIso 𝑆)) → (𝐹 ∘ 𝐺) ∈ (𝑅 RingIso 𝑇))
Theorem	ricsym 41399	Ring isomorphism is symmetric. (Contributed by SN, 10-Jan-2025.)
⊢ (𝑅 ≃𝑟 𝑆 → 𝑆 ≃𝑟 𝑅)
Theorem	rictr 41400	Ring isomorphism is transitive. (Contributed by SN, 17-Jan-2025.)
⊢ ((𝑅 ≃𝑟 𝑆 ∧ 𝑆 ≃𝑟 𝑇) → 𝑅 ≃𝑟 𝑇)