P. 196 of Theorem List - Metamath Proof Explorer

Theorem List for Metamath Proof Explorer - 19501-19600   *Has distinct variable group(s)

Type	Label	Description
Statement
Theorem	gsmsymgreqlem1 19501*	Lemma 1 for gsmsymgreq 19503. (Contributed by AV, 26-Jan-2019.)
⊢ 𝑆 = (SymGrp‘𝑁)    &   ⊢ 𝐵 = (Base‘𝑆)    &   ⊢ 𝑍 = (SymGrp‘𝑀)    &   ⊢ 𝑃 = (Base‘𝑍)    &   ⊢ 𝐼 = (𝑁 ∩ 𝑀)    ⇒   ⊢ (((𝑁 ∈ Fin ∧ 𝑀 ∈ Fin ∧ 𝐽 ∈ 𝐼) ∧ ((𝑋 ∈ Word 𝐵 ∧ 𝐶 ∈ 𝐵) ∧ (𝑌 ∈ Word 𝑃 ∧ 𝑅 ∈ 𝑃) ∧ (♯‘𝑋) = (♯‘𝑌))) → ((∀𝑛 ∈ 𝐼 ((𝑆 Σg 𝑋)‘𝑛) = ((𝑍 Σg 𝑌)‘𝑛) ∧ (𝐶‘𝐽) = (𝑅‘𝐽)) → ((𝑆 Σg (𝑋 ++ ⟨“𝐶”⟩))‘𝐽) = ((𝑍 Σg (𝑌 ++ ⟨“𝑅”⟩))‘𝐽)))
Theorem	gsmsymgreqlem2 19502*	Lemma 2 for gsmsymgreq 19503. (Contributed by AV, 26-Jan-2019.)
⊢ 𝑆 = (SymGrp‘𝑁)    &   ⊢ 𝐵 = (Base‘𝑆)    &   ⊢ 𝑍 = (SymGrp‘𝑀)    &   ⊢ 𝑃 = (Base‘𝑍)    &   ⊢ 𝐼 = (𝑁 ∩ 𝑀)    ⇒   ⊢ (((𝑁 ∈ Fin ∧ 𝑀 ∈ Fin) ∧ ((𝑋 ∈ Word 𝐵 ∧ 𝐶 ∈ 𝐵) ∧ (𝑌 ∈ Word 𝑃 ∧ 𝑅 ∈ 𝑃) ∧ (♯‘𝑋) = (♯‘𝑌))) → ((∀𝑖 ∈ (0..^(♯‘𝑋))∀𝑛 ∈ 𝐼 ((𝑋‘𝑖)‘𝑛) = ((𝑌‘𝑖)‘𝑛) → ∀𝑛 ∈ 𝐼 ((𝑆 Σg 𝑋)‘𝑛) = ((𝑍 Σg 𝑌)‘𝑛)) → (∀𝑖 ∈ (0..^(♯‘(𝑋 ++ ⟨“𝐶”⟩)))∀𝑛 ∈ 𝐼 (((𝑋 ++ ⟨“𝐶”⟩)‘𝑖)‘𝑛) = (((𝑌 ++ ⟨“𝑅”⟩)‘𝑖)‘𝑛) → ∀𝑛 ∈ 𝐼 ((𝑆 Σg (𝑋 ++ ⟨“𝐶”⟩))‘𝑛) = ((𝑍 Σg (𝑌 ++ ⟨“𝑅”⟩))‘𝑛))))
Theorem	gsmsymgreq 19503*	Two combination of permutations moves an element of the intersection of the base sets of the permutations to the same element if each pair of corresponding permutations moves such an element to the same element. (Contributed by AV, 20-Jan-2019.)
⊢ 𝑆 = (SymGrp‘𝑁)    &   ⊢ 𝐵 = (Base‘𝑆)    &   ⊢ 𝑍 = (SymGrp‘𝑀)    &   ⊢ 𝑃 = (Base‘𝑍)    &   ⊢ 𝐼 = (𝑁 ∩ 𝑀)    ⇒   ⊢ (((𝑁 ∈ Fin ∧ 𝑀 ∈ Fin) ∧ (𝑊 ∈ Word 𝐵 ∧ 𝑈 ∈ Word 𝑃 ∧ (♯‘𝑊) = (♯‘𝑈))) → (∀𝑖 ∈ (0..^(♯‘𝑊))∀𝑛 ∈ 𝐼 ((𝑊‘𝑖)‘𝑛) = ((𝑈‘𝑖)‘𝑛) → ∀𝑛 ∈ 𝐼 ((𝑆 Σg 𝑊)‘𝑛) = ((𝑍 Σg 𝑈)‘𝑛)))
Theorem	symgfixelq 19504*	A permutation of a set fixing an element of the set. (Contributed by AV, 4-Jan-2019.)
⊢ 𝑃 = (Base‘(SymGrp‘𝑁))    &   ⊢ 𝑄 = {𝑞 ∈ 𝑃 ∣ (𝑞‘𝐾) = 𝐾}    ⇒   ⊢ (𝐹 ∈ 𝑉 → (𝐹 ∈ 𝑄 ↔ (𝐹:𝑁–1-1-onto→𝑁 ∧ (𝐹‘𝐾) = 𝐾)))
Theorem	symgfixels 19505*	The restriction of a permutation to a set with one element removed is an element of the restricted symmetric group if the restriction is a 1-1 onto function. (Contributed by AV, 4-Jan-2019.)
⊢ 𝑃 = (Base‘(SymGrp‘𝑁))    &   ⊢ 𝑄 = {𝑞 ∈ 𝑃 ∣ (𝑞‘𝐾) = 𝐾}    &   ⊢ 𝑆 = (Base‘(SymGrp‘(𝑁 ∖ {𝐾})))    &   ⊢ 𝐷 = (𝑁 ∖ {𝐾})    ⇒   ⊢ (𝐹 ∈ 𝑉 → ((𝐹 ↾ 𝐷) ∈ 𝑆 ↔ (𝐹 ↾ 𝐷):𝐷–1-1-onto→𝐷))
Theorem	symgfixelsi 19506*	The restriction of a permutation fixing an element to the set with this element removed is an element of the restricted symmetric group. (Contributed by AV, 4-Jan-2019.)
⊢ 𝑃 = (Base‘(SymGrp‘𝑁))    &   ⊢ 𝑄 = {𝑞 ∈ 𝑃 ∣ (𝑞‘𝐾) = 𝐾}    &   ⊢ 𝑆 = (Base‘(SymGrp‘(𝑁 ∖ {𝐾})))    &   ⊢ 𝐷 = (𝑁 ∖ {𝐾})    ⇒   ⊢ ((𝐾 ∈ 𝑁 ∧ 𝐹 ∈ 𝑄) → (𝐹 ↾ 𝐷) ∈ 𝑆)
Theorem	symgfixf 19507*	The mapping of a permutation of a set fixing an element to a permutation of the set without the fixed element is a function. (Contributed by AV, 4-Jan-2019.)
⊢ 𝑃 = (Base‘(SymGrp‘𝑁))    &   ⊢ 𝑄 = {𝑞 ∈ 𝑃 ∣ (𝑞‘𝐾) = 𝐾}    &   ⊢ 𝑆 = (Base‘(SymGrp‘(𝑁 ∖ {𝐾})))    &   ⊢ 𝐻 = (𝑞 ∈ 𝑄 ↦ (𝑞 ↾ (𝑁 ∖ {𝐾})))    ⇒   ⊢ (𝐾 ∈ 𝑁 → 𝐻:𝑄⟶𝑆)
Theorem	symgfixf1 19508*	The mapping of a permutation of a set fixing an element to a permutation of the set without the fixed element is a 1-1 function. (Contributed by AV, 4-Jan-2019.)
⊢ 𝑃 = (Base‘(SymGrp‘𝑁))    &   ⊢ 𝑄 = {𝑞 ∈ 𝑃 ∣ (𝑞‘𝐾) = 𝐾}    &   ⊢ 𝑆 = (Base‘(SymGrp‘(𝑁 ∖ {𝐾})))    &   ⊢ 𝐻 = (𝑞 ∈ 𝑄 ↦ (𝑞 ↾ (𝑁 ∖ {𝐾})))    ⇒   ⊢ (𝐾 ∈ 𝑁 → 𝐻:𝑄–1-1→𝑆)
Theorem	symgfixfolem1 19509*	Lemma 1 for symgfixfo 19510. (Contributed by AV, 7-Jan-2019.)
⊢ 𝑃 = (Base‘(SymGrp‘𝑁))    &   ⊢ 𝑄 = {𝑞 ∈ 𝑃 ∣ (𝑞‘𝐾) = 𝐾}    &   ⊢ 𝑆 = (Base‘(SymGrp‘(𝑁 ∖ {𝐾})))    &   ⊢ 𝐻 = (𝑞 ∈ 𝑄 ↦ (𝑞 ↾ (𝑁 ∖ {𝐾})))    &   ⊢ 𝐸 = (𝑥 ∈ 𝑁 ↦ if(𝑥 = 𝐾, 𝐾, (𝑍‘𝑥)))    ⇒   ⊢ ((𝑁 ∈ 𝑉 ∧ 𝐾 ∈ 𝑁 ∧ 𝑍 ∈ 𝑆) → 𝐸 ∈ 𝑄)
Theorem	symgfixfo 19510*	The mapping of a permutation of a set fixing an element to a permutation of the set without the fixed element is an onto function. (Contributed by AV, 7-Jan-2019.)
⊢ 𝑃 = (Base‘(SymGrp‘𝑁))    &   ⊢ 𝑄 = {𝑞 ∈ 𝑃 ∣ (𝑞‘𝐾) = 𝐾}    &   ⊢ 𝑆 = (Base‘(SymGrp‘(𝑁 ∖ {𝐾})))    &   ⊢ 𝐻 = (𝑞 ∈ 𝑄 ↦ (𝑞 ↾ (𝑁 ∖ {𝐾})))    ⇒   ⊢ ((𝑁 ∈ 𝑉 ∧ 𝐾 ∈ 𝑁) → 𝐻:𝑄–onto→𝑆)
Theorem	symgfixf1o 19511*	The mapping of a permutation of a set fixing an element to a permutation of the set without the fixed element is a bijection. (Contributed by AV, 7-Jan-2019.)
⊢ 𝑃 = (Base‘(SymGrp‘𝑁))    &   ⊢ 𝑄 = {𝑞 ∈ 𝑃 ∣ (𝑞‘𝐾) = 𝐾}    &   ⊢ 𝑆 = (Base‘(SymGrp‘(𝑁 ∖ {𝐾})))    &   ⊢ 𝐻 = (𝑞 ∈ 𝑄 ↦ (𝑞 ↾ (𝑁 ∖ {𝐾})))    ⇒   ⊢ ((𝑁 ∈ 𝑉 ∧ 𝐾 ∈ 𝑁) → 𝐻:𝑄–1-1-onto→𝑆)
10.2.10.4  Transpositions in the symmetric group Transpositions are special cases of "cycles" as defined in [Rotman] p. 28: "Let i1 , i2 , ... , ir be distinct integers between 1 and n. If α in Sn fixes the other integers and α(i1) = i2, α(i2) = i3, ..., α(ir-1 ) = ir, α(ir) = i1, then α is an r-cycle. We also say that α is a cycle of length r." and in [Rotman] p. 31: "A 2-cycle is also called transposition.". We (currently) do not have/need a definition for cycles, so transpositions are explicitly defined in df-pmtr 19513.
Syntax	cpmtr 19512	Syntax for the transposition generator function.
class pmTrsp
Definition	df-pmtr 19513*	Define a function that generates the transpositions on a set. (Contributed by Stefan O'Rear, 16-Aug-2015.)
⊢ pmTrsp = (𝑑 ∈ V ↦ (𝑝 ∈ {𝑦 ∈ 𝒫 𝑑 ∣ 𝑦 ≈ 2o} ↦ (𝑧 ∈ 𝑑 ↦ if(𝑧 ∈ 𝑝, ∪ (𝑝 ∖ {𝑧}), 𝑧))))
Theorem	f1omvdmvd 19514	A permutation of any class moves a point which is moved to a different point which is moved. (Contributed by Stefan O'Rear, 22-Aug-2015.)
⊢ ((𝐹:𝐴–1-1-onto→𝐴 ∧ 𝑋 ∈ dom (𝐹 ∖ I )) → (𝐹‘𝑋) ∈ (dom (𝐹 ∖ I ) ∖ {𝑋}))
Theorem	f1omvdcnv 19515	A permutation and its inverse move the same points. (Contributed by Stefan O'Rear, 22-Aug-2015.)
⊢ (𝐹:𝐴–1-1-onto→𝐴 → dom (◡𝐹 ∖ I ) = dom (𝐹 ∖ I ))
Theorem	mvdco 19516	Composing two permutations moves at most the union of the points. (Contributed by Stefan O'Rear, 22-Aug-2015.)
⊢ dom ((𝐹 ∘ 𝐺) ∖ I ) ⊆ (dom (𝐹 ∖ I ) ∪ dom (𝐺 ∖ I ))
Theorem	f1omvdconj 19517	Conjugation of a permutation takes the image of the moved subclass. (Contributed by Stefan O'Rear, 22-Aug-2015.)
⊢ ((𝐹:𝐴⟶𝐴 ∧ 𝐺:𝐴–1-1-onto→𝐴) → dom (((𝐺 ∘ 𝐹) ∘ ◡𝐺) ∖ I ) = (𝐺 “ dom (𝐹 ∖ I )))
Theorem	f1otrspeq 19518	A transposition is characterized by the points it moves. (Contributed by Stefan O'Rear, 22-Aug-2015.)
⊢ (((𝐹:𝐴–1-1-onto→𝐴 ∧ 𝐺:𝐴–1-1-onto→𝐴) ∧ (dom (𝐹 ∖ I ) ≈ 2o ∧ dom (𝐺 ∖ I ) = dom (𝐹 ∖ I ))) → 𝐹 = 𝐺)
Theorem	f1omvdco2 19519	If exactly one of two permutations is limited to a set of points, then the composition will not be. (Contributed by Stefan O'Rear, 23-Aug-2015.)
⊢ ((𝐹:𝐴–1-1-onto→𝐴 ∧ 𝐺:𝐴–1-1-onto→𝐴 ∧ (dom (𝐹 ∖ I ) ⊆ 𝑋 ⊻ dom (𝐺 ∖ I ) ⊆ 𝑋)) → ¬ dom ((𝐹 ∘ 𝐺) ∖ I ) ⊆ 𝑋)
Theorem	f1omvdco3 19520	If a point is moved by exactly one of two permutations, then it will be moved by their composite. (Contributed by Stefan O'Rear, 23-Aug-2015.)
⊢ ((𝐹:𝐴–1-1-onto→𝐴 ∧ 𝐺:𝐴–1-1-onto→𝐴 ∧ (𝑋 ∈ dom (𝐹 ∖ I ) ⊻ 𝑋 ∈ dom (𝐺 ∖ I ))) → 𝑋 ∈ dom ((𝐹 ∘ 𝐺) ∖ I ))
Theorem	pmtrfval 19521*	The function generating transpositions on a set. (Contributed by Stefan O'Rear, 16-Aug-2015.)
⊢ 𝑇 = (pmTrsp‘𝐷)    ⇒   ⊢ (𝐷 ∈ 𝑉 → 𝑇 = (𝑝 ∈ {𝑦 ∈ 𝒫 𝐷 ∣ 𝑦 ≈ 2o} ↦ (𝑧 ∈ 𝐷 ↦ if(𝑧 ∈ 𝑝, ∪ (𝑝 ∖ {𝑧}), 𝑧))))
Theorem	pmtrval 19522*	A generated transposition, expressed in a symmetric form. (Contributed by Stefan O'Rear, 16-Aug-2015.)
⊢ 𝑇 = (pmTrsp‘𝐷)    ⇒   ⊢ ((𝐷 ∈ 𝑉 ∧ 𝑃 ⊆ 𝐷 ∧ 𝑃 ≈ 2o) → (𝑇‘𝑃) = (𝑧 ∈ 𝐷 ↦ if(𝑧 ∈ 𝑃, ∪ (𝑃 ∖ {𝑧}), 𝑧)))
Theorem	pmtrfv 19523	General value of mapping a point under a transposition. (Contributed by Stefan O'Rear, 16-Aug-2015.)
⊢ 𝑇 = (pmTrsp‘𝐷)    ⇒   ⊢ (((𝐷 ∈ 𝑉 ∧ 𝑃 ⊆ 𝐷 ∧ 𝑃 ≈ 2o) ∧ 𝑍 ∈ 𝐷) → ((𝑇‘𝑃)‘𝑍) = if(𝑍 ∈ 𝑃, ∪ (𝑃 ∖ {𝑍}), 𝑍))
Theorem	pmtrprfv 19524	In a transposition of two given points, each maps to the other. (Contributed by Stefan O'Rear, 25-Aug-2015.)
⊢ 𝑇 = (pmTrsp‘𝐷)    ⇒   ⊢ ((𝐷 ∈ 𝑉 ∧ (𝑋 ∈ 𝐷 ∧ 𝑌 ∈ 𝐷 ∧ 𝑋 ≠ 𝑌)) → ((𝑇‘{𝑋, 𝑌})‘𝑋) = 𝑌)
Theorem	pmtrprfv3 19525	In a transposition of two given points, all other points are mapped to themselves. (Contributed by AV, 17-Mar-2019.)
⊢ 𝑇 = (pmTrsp‘𝐷)    ⇒   ⊢ ((𝐷 ∈ 𝑉 ∧ (𝑋 ∈ 𝐷 ∧ 𝑌 ∈ 𝐷 ∧ 𝑍 ∈ 𝐷) ∧ (𝑋 ≠ 𝑌 ∧ 𝑋 ≠ 𝑍 ∧ 𝑌 ≠ 𝑍)) → ((𝑇‘{𝑋, 𝑌})‘𝑍) = 𝑍)
Theorem	pmtrf 19526	Functionality of a transposition. (Contributed by Stefan O'Rear, 16-Aug-2015.)
⊢ 𝑇 = (pmTrsp‘𝐷)    ⇒   ⊢ ((𝐷 ∈ 𝑉 ∧ 𝑃 ⊆ 𝐷 ∧ 𝑃 ≈ 2o) → (𝑇‘𝑃):𝐷⟶𝐷)
Theorem	pmtrmvd 19527	A transposition moves precisely the transposed points. (Contributed by Stefan O'Rear, 16-Aug-2015.)
⊢ 𝑇 = (pmTrsp‘𝐷)    ⇒   ⊢ ((𝐷 ∈ 𝑉 ∧ 𝑃 ⊆ 𝐷 ∧ 𝑃 ≈ 2o) → dom ((𝑇‘𝑃) ∖ I ) = 𝑃)
Theorem	pmtrrn 19528	Transposing two points gives a transposition function. (Contributed by Stefan O'Rear, 22-Aug-2015.)
⊢ 𝑇 = (pmTrsp‘𝐷)    &   ⊢ 𝑅 = ran 𝑇    ⇒   ⊢ ((𝐷 ∈ 𝑉 ∧ 𝑃 ⊆ 𝐷 ∧ 𝑃 ≈ 2o) → (𝑇‘𝑃) ∈ 𝑅)
Theorem	pmtrfrn 19529	A transposition (as a kind of function) is the function transposing the two points it moves. (Contributed by Stefan O'Rear, 22-Aug-2015.)
⊢ 𝑇 = (pmTrsp‘𝐷)    &   ⊢ 𝑅 = ran 𝑇    &   ⊢ 𝑃 = dom (𝐹 ∖ I )    ⇒   ⊢ (𝐹 ∈ 𝑅 → ((𝐷 ∈ V ∧ 𝑃 ⊆ 𝐷 ∧ 𝑃 ≈ 2o) ∧ 𝐹 = (𝑇‘𝑃)))
Theorem	pmtrffv 19530	Mapping of a point under a transposition function. (Contributed by Stefan O'Rear, 22-Aug-2015.)
⊢ 𝑇 = (pmTrsp‘𝐷)    &   ⊢ 𝑅 = ran 𝑇    &   ⊢ 𝑃 = dom (𝐹 ∖ I )    ⇒   ⊢ ((𝐹 ∈ 𝑅 ∧ 𝑍 ∈ 𝐷) → (𝐹‘𝑍) = if(𝑍 ∈ 𝑃, ∪ (𝑃 ∖ {𝑍}), 𝑍))
Theorem	pmtrrn2 19531*	For any transposition there are two points it is transposing. (Contributed by SO, 15-Jul-2018.)
⊢ 𝑇 = (pmTrsp‘𝐷)    &   ⊢ 𝑅 = ran 𝑇    ⇒   ⊢ (𝐹 ∈ 𝑅 → ∃𝑥 ∈ 𝐷 ∃𝑦 ∈ 𝐷 (𝑥 ≠ 𝑦 ∧ 𝐹 = (𝑇‘{𝑥, 𝑦})))
Theorem	pmtrfinv 19532	A transposition function is an involution. (Contributed by Stefan O'Rear, 22-Aug-2015.)
⊢ 𝑇 = (pmTrsp‘𝐷)    &   ⊢ 𝑅 = ran 𝑇    ⇒   ⊢ (𝐹 ∈ 𝑅 → (𝐹 ∘ 𝐹) = ( I ↾ 𝐷))
Theorem	pmtrfmvdn0 19533	A transposition moves at least one point. (Contributed by Stefan O'Rear, 23-Aug-2015.)
⊢ 𝑇 = (pmTrsp‘𝐷)    &   ⊢ 𝑅 = ran 𝑇    ⇒   ⊢ (𝐹 ∈ 𝑅 → dom (𝐹 ∖ I ) ≠ ∅)
Theorem	pmtrff1o 19534	A transposition function is a permutation. (Contributed by Stefan O'Rear, 22-Aug-2015.)
⊢ 𝑇 = (pmTrsp‘𝐷)    &   ⊢ 𝑅 = ran 𝑇    ⇒   ⊢ (𝐹 ∈ 𝑅 → 𝐹:𝐷–1-1-onto→𝐷)
Theorem	pmtrfcnv 19535	A transposition function is its own inverse. (Contributed by Stefan O'Rear, 22-Aug-2015.)
⊢ 𝑇 = (pmTrsp‘𝐷)    &   ⊢ 𝑅 = ran 𝑇    ⇒   ⊢ (𝐹 ∈ 𝑅 → ◡𝐹 = 𝐹)
Theorem	pmtrfb 19536	An intrinsic characterization of the transposition permutations. (Contributed by Stefan O'Rear, 22-Aug-2015.)
⊢ 𝑇 = (pmTrsp‘𝐷)    &   ⊢ 𝑅 = ran 𝑇    ⇒   ⊢ (𝐹 ∈ 𝑅 ↔ (𝐷 ∈ V ∧ 𝐹:𝐷–1-1-onto→𝐷 ∧ dom (𝐹 ∖ I ) ≈ 2o))
Theorem	pmtrfconj 19537	Any conjugate of a transposition is a transposition. (Contributed by Stefan O'Rear, 22-Aug-2015.)
⊢ 𝑇 = (pmTrsp‘𝐷)    &   ⊢ 𝑅 = ran 𝑇    ⇒   ⊢ ((𝐹 ∈ 𝑅 ∧ 𝐺:𝐷–1-1-onto→𝐷) → ((𝐺 ∘ 𝐹) ∘ ◡𝐺) ∈ 𝑅)
Theorem	symgsssg 19538*	The symmetric group has subgroups restricting the set of non-fixed points. (Contributed by Stefan O'Rear, 24-Aug-2015.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝐵 = (Base‘𝐺)    ⇒   ⊢ (𝐷 ∈ 𝑉 → {𝑥 ∈ 𝐵 ∣ dom (𝑥 ∖ I ) ⊆ 𝑋} ∈ (SubGrp‘𝐺))
Theorem	symgfisg 19539*	The symmetric group has a subgroup of permutations that move finitely many points. (Contributed by Stefan O'Rear, 24-Aug-2015.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝐵 = (Base‘𝐺)    ⇒   ⊢ (𝐷 ∈ 𝑉 → {𝑥 ∈ 𝐵 ∣ dom (𝑥 ∖ I ) ∈ Fin} ∈ (SubGrp‘𝐺))
Theorem	symgtrf 19540	Transpositions are elements of the symmetric group. (Contributed by Stefan O'Rear, 23-Aug-2015.)
⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝐵 = (Base‘𝐺)    ⇒   ⊢ 𝑇 ⊆ 𝐵
Theorem	symggen 19541*	The span of the transpositions is the subgroup that moves finitely many points. (Contributed by Stefan O'Rear, 28-Aug-2015.)
⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝐵 = (Base‘𝐺)    &   ⊢ 𝐾 = (mrCls‘(SubMnd‘𝐺))    ⇒   ⊢ (𝐷 ∈ 𝑉 → (𝐾‘𝑇) = {𝑥 ∈ 𝐵 ∣ dom (𝑥 ∖ I ) ∈ Fin})
Theorem	symggen2 19542	A finite permutation group is generated by the transpositions, see also Theorem 3.4 in [Rotman] p. 31. (Contributed by Stefan O'Rear, 28-Aug-2015.)
⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝐵 = (Base‘𝐺)    &   ⊢ 𝐾 = (mrCls‘(SubMnd‘𝐺))    ⇒   ⊢ (𝐷 ∈ Fin → (𝐾‘𝑇) = 𝐵)
Theorem	symgtrinv 19543	To invert a permutation represented as a sequence of transpositions, reverse the sequence. (Contributed by Stefan O'Rear, 27-Aug-2015.)
⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝐼 = (invg‘𝐺)    ⇒   ⊢ ((𝐷 ∈ 𝑉 ∧ 𝑊 ∈ Word 𝑇) → (𝐼‘(𝐺 Σg 𝑊)) = (𝐺 Σg (reverse‘𝑊)))
Theorem	pmtr3ncomlem1 19544	Lemma 1 for pmtr3ncom 19546. (Contributed by AV, 17-Mar-2018.)
⊢ 𝑇 = (pmTrsp‘𝐷)    &   ⊢ 𝐹 = (𝑇‘{𝑋, 𝑌})    &   ⊢ 𝐺 = (𝑇‘{𝑌, 𝑍})    ⇒   ⊢ ((𝐷 ∈ 𝑉 ∧ (𝑋 ∈ 𝐷 ∧ 𝑌 ∈ 𝐷 ∧ 𝑍 ∈ 𝐷) ∧ (𝑋 ≠ 𝑌 ∧ 𝑋 ≠ 𝑍 ∧ 𝑌 ≠ 𝑍)) → ((𝐺 ∘ 𝐹)‘𝑋) ≠ ((𝐹 ∘ 𝐺)‘𝑋))
Theorem	pmtr3ncomlem2 19545	Lemma 2 for pmtr3ncom 19546. (Contributed by AV, 17-Mar-2018.)
⊢ 𝑇 = (pmTrsp‘𝐷)    &   ⊢ 𝐹 = (𝑇‘{𝑋, 𝑌})    &   ⊢ 𝐺 = (𝑇‘{𝑌, 𝑍})    ⇒   ⊢ ((𝐷 ∈ 𝑉 ∧ (𝑋 ∈ 𝐷 ∧ 𝑌 ∈ 𝐷 ∧ 𝑍 ∈ 𝐷) ∧ (𝑋 ≠ 𝑌 ∧ 𝑋 ≠ 𝑍 ∧ 𝑌 ≠ 𝑍)) → (𝐺 ∘ 𝐹) ≠ (𝐹 ∘ 𝐺))
Theorem	pmtr3ncom 19546*	Transpositions over sets with at least 3 elements are not commutative, see also the remark in [Rotman] p. 28. (Contributed by AV, 21-Mar-2019.)
⊢ 𝑇 = (pmTrsp‘𝐷)    ⇒   ⊢ ((𝐷 ∈ 𝑉 ∧ 3 ≤ (♯‘𝐷)) → ∃𝑓 ∈ ran 𝑇∃𝑔 ∈ ran 𝑇(𝑔 ∘ 𝑓) ≠ (𝑓 ∘ 𝑔))
Theorem	pmtrdifellem1 19547	Lemma 1 for pmtrdifel 19551. (Contributed by AV, 15-Jan-2019.)
⊢ 𝑇 = ran (pmTrsp‘(𝑁 ∖ {𝐾}))    &   ⊢ 𝑅 = ran (pmTrsp‘𝑁)    &   ⊢ 𝑆 = ((pmTrsp‘𝑁)‘dom (𝑄 ∖ I ))    ⇒   ⊢ (𝑄 ∈ 𝑇 → 𝑆 ∈ 𝑅)
Theorem	pmtrdifellem2 19548	Lemma 2 for pmtrdifel 19551. (Contributed by AV, 15-Jan-2019.)
⊢ 𝑇 = ran (pmTrsp‘(𝑁 ∖ {𝐾}))    &   ⊢ 𝑅 = ran (pmTrsp‘𝑁)    &   ⊢ 𝑆 = ((pmTrsp‘𝑁)‘dom (𝑄 ∖ I ))    ⇒   ⊢ (𝑄 ∈ 𝑇 → dom (𝑆 ∖ I ) = dom (𝑄 ∖ I ))
Theorem	pmtrdifellem3 19549*	Lemma 3 for pmtrdifel 19551. (Contributed by AV, 15-Jan-2019.)
⊢ 𝑇 = ran (pmTrsp‘(𝑁 ∖ {𝐾}))    &   ⊢ 𝑅 = ran (pmTrsp‘𝑁)    &   ⊢ 𝑆 = ((pmTrsp‘𝑁)‘dom (𝑄 ∖ I ))    ⇒   ⊢ (𝑄 ∈ 𝑇 → ∀𝑥 ∈ (𝑁 ∖ {𝐾})(𝑄‘𝑥) = (𝑆‘𝑥))
Theorem	pmtrdifellem4 19550	Lemma 4 for pmtrdifel 19551. (Contributed by AV, 28-Jan-2019.)
⊢ 𝑇 = ran (pmTrsp‘(𝑁 ∖ {𝐾}))    &   ⊢ 𝑅 = ran (pmTrsp‘𝑁)    &   ⊢ 𝑆 = ((pmTrsp‘𝑁)‘dom (𝑄 ∖ I ))    ⇒   ⊢ ((𝑄 ∈ 𝑇 ∧ 𝐾 ∈ 𝑁) → (𝑆‘𝐾) = 𝐾)
Theorem	pmtrdifel 19551*	A transposition of elements of a set without a special element corresponds to a transposition of elements of the set. (Contributed by AV, 15-Jan-2019.)
⊢ 𝑇 = ran (pmTrsp‘(𝑁 ∖ {𝐾}))    &   ⊢ 𝑅 = ran (pmTrsp‘𝑁)    ⇒   ⊢ ∀𝑡 ∈ 𝑇 ∃𝑟 ∈ 𝑅 ∀𝑥 ∈ (𝑁 ∖ {𝐾})(𝑡‘𝑥) = (𝑟‘𝑥)
Theorem	pmtrdifwrdellem1 19552*	Lemma 1 for pmtrdifwrdel 19556. (Contributed by AV, 15-Jan-2019.)
⊢ 𝑇 = ran (pmTrsp‘(𝑁 ∖ {𝐾}))    &   ⊢ 𝑅 = ran (pmTrsp‘𝑁)    &   ⊢ 𝑈 = (𝑥 ∈ (0..^(♯‘𝑊)) ↦ ((pmTrsp‘𝑁)‘dom ((𝑊‘𝑥) ∖ I )))    ⇒   ⊢ (𝑊 ∈ Word 𝑇 → 𝑈 ∈ Word 𝑅)
Theorem	pmtrdifwrdellem2 19553*	Lemma 2 for pmtrdifwrdel 19556. (Contributed by AV, 15-Jan-2019.)
⊢ 𝑇 = ran (pmTrsp‘(𝑁 ∖ {𝐾}))    &   ⊢ 𝑅 = ran (pmTrsp‘𝑁)    &   ⊢ 𝑈 = (𝑥 ∈ (0..^(♯‘𝑊)) ↦ ((pmTrsp‘𝑁)‘dom ((𝑊‘𝑥) ∖ I )))    ⇒   ⊢ (𝑊 ∈ Word 𝑇 → (♯‘𝑊) = (♯‘𝑈))
Theorem	pmtrdifwrdellem3 19554*	Lemma 3 for pmtrdifwrdel 19556. (Contributed by AV, 15-Jan-2019.)
⊢ 𝑇 = ran (pmTrsp‘(𝑁 ∖ {𝐾}))    &   ⊢ 𝑅 = ran (pmTrsp‘𝑁)    &   ⊢ 𝑈 = (𝑥 ∈ (0..^(♯‘𝑊)) ↦ ((pmTrsp‘𝑁)‘dom ((𝑊‘𝑥) ∖ I )))    ⇒   ⊢ (𝑊 ∈ Word 𝑇 → ∀𝑖 ∈ (0..^(♯‘𝑊))∀𝑛 ∈ (𝑁 ∖ {𝐾})((𝑊‘𝑖)‘𝑛) = ((𝑈‘𝑖)‘𝑛))
Theorem	pmtrdifwrdel2lem1 19555*	Lemma 1 for pmtrdifwrdel2 19557. (Contributed by AV, 31-Jan-2019.)
⊢ 𝑇 = ran (pmTrsp‘(𝑁 ∖ {𝐾}))    &   ⊢ 𝑅 = ran (pmTrsp‘𝑁)    &   ⊢ 𝑈 = (𝑥 ∈ (0..^(♯‘𝑊)) ↦ ((pmTrsp‘𝑁)‘dom ((𝑊‘𝑥) ∖ I )))    ⇒   ⊢ ((𝑊 ∈ Word 𝑇 ∧ 𝐾 ∈ 𝑁) → ∀𝑖 ∈ (0..^(♯‘𝑊))((𝑈‘𝑖)‘𝐾) = 𝐾)
Theorem	pmtrdifwrdel 19556*	A sequence of transpositions of elements of a set without a special element corresponds to a sequence of transpositions of elements of the set. (Contributed by AV, 15-Jan-2019.)
⊢ 𝑇 = ran (pmTrsp‘(𝑁 ∖ {𝐾}))    &   ⊢ 𝑅 = ran (pmTrsp‘𝑁)    ⇒   ⊢ ∀𝑤 ∈ Word 𝑇∃𝑢 ∈ Word 𝑅((♯‘𝑤) = (♯‘𝑢) ∧ ∀𝑖 ∈ (0..^(♯‘𝑤))∀𝑥 ∈ (𝑁 ∖ {𝐾})((𝑤‘𝑖)‘𝑥) = ((𝑢‘𝑖)‘𝑥))
Theorem	pmtrdifwrdel2 19557*	A sequence of transpositions of elements of a set without a special element corresponds to a sequence of transpositions of elements of the set not moving the special element. (Contributed by AV, 31-Jan-2019.)
⊢ 𝑇 = ran (pmTrsp‘(𝑁 ∖ {𝐾}))    &   ⊢ 𝑅 = ran (pmTrsp‘𝑁)    ⇒   ⊢ (𝐾 ∈ 𝑁 → ∀𝑤 ∈ Word 𝑇∃𝑢 ∈ Word 𝑅((♯‘𝑤) = (♯‘𝑢) ∧ ∀𝑖 ∈ (0..^(♯‘𝑤))(((𝑢‘𝑖)‘𝐾) = 𝐾 ∧ ∀𝑥 ∈ (𝑁 ∖ {𝐾})((𝑤‘𝑖)‘𝑥) = ((𝑢‘𝑖)‘𝑥))))
Theorem	pmtrprfval 19558*	The transpositions on a pair. (Contributed by AV, 9-Dec-2018.)
⊢ (pmTrsp‘{1, 2}) = (𝑝 ∈ {{1, 2}} ↦ (𝑧 ∈ {1, 2} ↦ if(𝑧 = 1, 2, 1)))
Theorem	pmtrprfvalrn 19559	The range of the transpositions on a pair is actually a singleton: the transposition of the two elements of the pair. (Contributed by AV, 9-Dec-2018.)
⊢ ran (pmTrsp‘{1, 2}) = {{⟨1, 2⟩, ⟨2, 1⟩}}
10.2.10.5  The sign of a permutation
Syntax	cpsgn 19560	Syntax for the sign of a permutation.
class pmSgn
Syntax	cevpm 19561	Syntax for even permutations.
class pmEven
Definition	df-psgn 19562*	Define a function which takes the value 1 for even permutations and -1 for odd. (Contributed by Stefan O'Rear, 28-Aug-2015.)
⊢ pmSgn = (𝑑 ∈ V ↦ (𝑥 ∈ {𝑝 ∈ (Base‘(SymGrp‘𝑑)) ∣ dom (𝑝 ∖ I ) ∈ Fin} ↦ (℩𝑠∃𝑤 ∈ Word ran (pmTrsp‘𝑑)(𝑥 = ((SymGrp‘𝑑) Σg 𝑤) ∧ 𝑠 = (-1↑(♯‘𝑤))))))
Definition	df-evpm 19563	Define the set of even permutations on a given set. (Contributed by Stefan O'Rear, 9-Jul-2018.)
⊢ pmEven = (𝑑 ∈ V ↦ (◡(pmSgn‘𝑑) “ {1}))
Theorem	psgnunilem1 19564*	Lemma for psgnuni 19570. Given two consequtive transpositions in a representation of a permutation, either they are equal and therefore equivalent to the identity, or they are not and it is possible to commute them such that a chosen point in the left transposition is preserved in the right. By repeating this process, a point can be removed from a representation of the identity. (Contributed by Stefan O'Rear, 22-Aug-2015.)
⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ (𝜑 → 𝐷 ∈ 𝑉)    &   ⊢ (𝜑 → 𝑃 ∈ 𝑇)    &   ⊢ (𝜑 → 𝑄 ∈ 𝑇)    &   ⊢ (𝜑 → 𝐴 ∈ dom (𝑃 ∖ I ))    ⇒   ⊢ (𝜑 → ((𝑃 ∘ 𝑄) = ( I ↾ 𝐷) ∨ ∃𝑟 ∈ 𝑇 ∃𝑠 ∈ 𝑇 ((𝑃 ∘ 𝑄) = (𝑟 ∘ 𝑠) ∧ 𝐴 ∈ dom (𝑠 ∖ I ) ∧ ¬ 𝐴 ∈ dom (𝑟 ∖ I ))))
Theorem	psgnunilem5 19565*	Lemma for psgnuni 19570. It is impossible to shift a transposition off the end because if the active transposition is at the right end, it is the only transposition moving 𝐴 in contradiction to this being a representation of the identity. (Contributed by Stefan O'Rear, 25-Aug-2015.) (Revised by Mario Carneiro, 28-Feb-2016.) (Proof shortened by AV, 12-Oct-2022.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ (𝜑 → 𝐷 ∈ 𝑉)    &   ⊢ (𝜑 → 𝑊 ∈ Word 𝑇)    &   ⊢ (𝜑 → (𝐺 Σg 𝑊) = ( I ↾ 𝐷))    &   ⊢ (𝜑 → (♯‘𝑊) = 𝐿)    &   ⊢ (𝜑 → 𝐼 ∈ (0..^𝐿))    &   ⊢ (𝜑 → 𝐴 ∈ dom ((𝑊‘𝐼) ∖ I ))    &   ⊢ (𝜑 → ∀𝑘 ∈ (0..^𝐼) ¬ 𝐴 ∈ dom ((𝑊‘𝑘) ∖ I ))    ⇒   ⊢ (𝜑 → (𝐼 + 1) ∈ (0..^𝐿))
Theorem	psgnunilem2 19566*	Lemma for psgnuni 19570. Induction step for moving a transposition as far to the right as possible. (Contributed by Stefan O'Rear, 24-Aug-2015.) (Revised by Mario Carneiro, 28-Feb-2016.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ (𝜑 → 𝐷 ∈ 𝑉)    &   ⊢ (𝜑 → 𝑊 ∈ Word 𝑇)    &   ⊢ (𝜑 → (𝐺 Σg 𝑊) = ( I ↾ 𝐷))    &   ⊢ (𝜑 → (♯‘𝑊) = 𝐿)    &   ⊢ (𝜑 → 𝐼 ∈ (0..^𝐿))    &   ⊢ (𝜑 → 𝐴 ∈ dom ((𝑊‘𝐼) ∖ I ))    &   ⊢ (𝜑 → ∀𝑘 ∈ (0..^𝐼) ¬ 𝐴 ∈ dom ((𝑊‘𝑘) ∖ I ))    &   ⊢ (𝜑 → ¬ ∃𝑥 ∈ Word 𝑇((♯‘𝑥) = (𝐿 − 2) ∧ (𝐺 Σg 𝑥) = ( I ↾ 𝐷)))    ⇒   ⊢ (𝜑 → ∃𝑤 ∈ Word 𝑇(((𝐺 Σg 𝑤) = ( I ↾ 𝐷) ∧ (♯‘𝑤) = 𝐿) ∧ ((𝐼 + 1) ∈ (0..^𝐿) ∧ 𝐴 ∈ dom ((𝑤‘(𝐼 + 1)) ∖ I ) ∧ ∀𝑗 ∈ (0..^(𝐼 + 1)) ¬ 𝐴 ∈ dom ((𝑤‘𝑗) ∖ I ))))
Theorem	psgnunilem3 19567*	Lemma for psgnuni 19570. Any nonempty representation of the identity can be incrementally transformed into a representation two shorter. (Contributed by Stefan O'Rear, 25-Aug-2015.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ (𝜑 → 𝐷 ∈ 𝑉)    &   ⊢ (𝜑 → 𝑊 ∈ Word 𝑇)    &   ⊢ (𝜑 → (♯‘𝑊) = 𝐿)    &   ⊢ (𝜑 → (♯‘𝑊) ∈ ℕ)    &   ⊢ (𝜑 → (𝐺 Σg 𝑊) = ( I ↾ 𝐷))    &   ⊢ (𝜑 → ¬ ∃𝑥 ∈ Word 𝑇((♯‘𝑥) = (𝐿 − 2) ∧ (𝐺 Σg 𝑥) = ( I ↾ 𝐷)))    ⇒   ⊢ ¬ 𝜑
Theorem	psgnunilem4 19568	Lemma for psgnuni 19570. An odd-length representation of the identity is impossible, as it could be repeatedly shortened to a length of 1, but a length 1 permutation must be a transposition. (Contributed by Stefan O'Rear, 25-Aug-2015.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ (𝜑 → 𝐷 ∈ 𝑉)    &   ⊢ (𝜑 → 𝑊 ∈ Word 𝑇)    &   ⊢ (𝜑 → (𝐺 Σg 𝑊) = ( I ↾ 𝐷))    ⇒   ⊢ (𝜑 → (-1↑(♯‘𝑊)) = 1)
Theorem	m1expaddsub 19569	Addition and subtraction of parities are the same. (Contributed by Stefan O'Rear, 27-Aug-2015.)
⊢ ((𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ) → (-1↑(𝑋 − 𝑌)) = (-1↑(𝑋 + 𝑌)))
Theorem	psgnuni 19570	If the same permutation can be written in more than one way as a product of transpositions, the parity of those products must agree; otherwise the product of one with the inverse of the other would be an odd representation of the identity. (Contributed by Stefan O'Rear, 27-Aug-2015.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ (𝜑 → 𝐷 ∈ 𝑉)    &   ⊢ (𝜑 → 𝑊 ∈ Word 𝑇)    &   ⊢ (𝜑 → 𝑋 ∈ Word 𝑇)    &   ⊢ (𝜑 → (𝐺 Σg 𝑊) = (𝐺 Σg 𝑋))    ⇒   ⊢ (𝜑 → (-1↑(♯‘𝑊)) = (-1↑(♯‘𝑋)))
Theorem	psgnfval 19571*	Function definition of the permutation sign function. (Contributed by Stefan O'Rear, 28-Aug-2015.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝐵 = (Base‘𝐺)    &   ⊢ 𝐹 = {𝑝 ∈ 𝐵 ∣ dom (𝑝 ∖ I ) ∈ Fin}    &   ⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ 𝑁 = (pmSgn‘𝐷)    ⇒   ⊢ 𝑁 = (𝑥 ∈ 𝐹 ↦ (℩𝑠∃𝑤 ∈ Word 𝑇(𝑥 = (𝐺 Σg 𝑤) ∧ 𝑠 = (-1↑(♯‘𝑤)))))
Theorem	psgnfn 19572*	Functionality and domain of the permutation sign function. (Contributed by Stefan O'Rear, 28-Aug-2015.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝐵 = (Base‘𝐺)    &   ⊢ 𝐹 = {𝑝 ∈ 𝐵 ∣ dom (𝑝 ∖ I ) ∈ Fin}    &   ⊢ 𝑁 = (pmSgn‘𝐷)    ⇒   ⊢ 𝑁 Fn 𝐹
Theorem	psgndmsubg 19573	The finitary permutations are a subgroup. (Contributed by Stefan O'Rear, 28-Aug-2015.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝑁 = (pmSgn‘𝐷)    ⇒   ⊢ (𝐷 ∈ 𝑉 → dom 𝑁 ∈ (SubGrp‘𝐺))
Theorem	psgneldm 19574	Property of being a finitary permutation. (Contributed by Stefan O'Rear, 28-Aug-2015.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝑁 = (pmSgn‘𝐷)    &   ⊢ 𝐵 = (Base‘𝐺)    ⇒   ⊢ (𝑃 ∈ dom 𝑁 ↔ (𝑃 ∈ 𝐵 ∧ dom (𝑃 ∖ I ) ∈ Fin))
Theorem	psgneldm2 19575*	The finitary permutations are the span of the transpositions. (Contributed by Stefan O'Rear, 28-Aug-2015.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ 𝑁 = (pmSgn‘𝐷)    ⇒   ⊢ (𝐷 ∈ 𝑉 → (𝑃 ∈ dom 𝑁 ↔ ∃𝑤 ∈ Word 𝑇𝑃 = (𝐺 Σg 𝑤)))
Theorem	psgneldm2i 19576	A sequence of transpositions describes a finitary permutation. (Contributed by Stefan O'Rear, 28-Aug-2015.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ 𝑁 = (pmSgn‘𝐷)    ⇒   ⊢ ((𝐷 ∈ 𝑉 ∧ 𝑊 ∈ Word 𝑇) → (𝐺 Σg 𝑊) ∈ dom 𝑁)
Theorem	psgneu 19577*	A finitary permutation has exactly one parity. (Contributed by Stefan O'Rear, 28-Aug-2015.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ 𝑁 = (pmSgn‘𝐷)    ⇒   ⊢ (𝑃 ∈ dom 𝑁 → ∃!𝑠∃𝑤 ∈ Word 𝑇(𝑃 = (𝐺 Σg 𝑤) ∧ 𝑠 = (-1↑(♯‘𝑤))))
Theorem	psgnval 19578*	Value of the permutation sign function. (Contributed by Stefan O'Rear, 28-Aug-2015.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ 𝑁 = (pmSgn‘𝐷)    ⇒   ⊢ (𝑃 ∈ dom 𝑁 → (𝑁‘𝑃) = (℩𝑠∃𝑤 ∈ Word 𝑇(𝑃 = (𝐺 Σg 𝑤) ∧ 𝑠 = (-1↑(♯‘𝑤)))))
Theorem	psgnvali 19579*	A finitary permutation has at least one representation for its parity. (Contributed by Stefan O'Rear, 28-Aug-2015.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ 𝑁 = (pmSgn‘𝐷)    ⇒   ⊢ (𝑃 ∈ dom 𝑁 → ∃𝑤 ∈ Word 𝑇(𝑃 = (𝐺 Σg 𝑤) ∧ (𝑁‘𝑃) = (-1↑(♯‘𝑤))))
Theorem	psgnvalii 19580	Any representation of a permutation is length matching the permutation sign. (Contributed by Stefan O'Rear, 28-Aug-2015.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ 𝑁 = (pmSgn‘𝐷)    ⇒   ⊢ ((𝐷 ∈ 𝑉 ∧ 𝑊 ∈ Word 𝑇) → (𝑁‘(𝐺 Σg 𝑊)) = (-1↑(♯‘𝑊)))
Theorem	psgnpmtr 19581	All transpositions are odd. (Contributed by Stefan O'Rear, 29-Aug-2015.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ 𝑁 = (pmSgn‘𝐷)    ⇒   ⊢ (𝑃 ∈ 𝑇 → (𝑁‘𝑃) = -1)
Theorem	psgn0fv0 19582	The permutation sign function for an empty set at an empty set is 1. (Contributed by AV, 27-Feb-2019.)
⊢ ((pmSgn‘∅)‘∅) = 1
Theorem	sygbasnfpfi 19583	The class of non-fixed points of a permutation of a finite set is finite. (Contributed by AV, 13-Jan-2019.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝐵 = (Base‘𝐺)    ⇒   ⊢ ((𝐷 ∈ Fin ∧ 𝑃 ∈ 𝐵) → dom (𝑃 ∖ I ) ∈ Fin)
Theorem	psgnfvalfi 19584*	Function definition of the permutation sign function for permutations of finite sets. (Contributed by AV, 13-Jan-2019.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝐵 = (Base‘𝐺)    &   ⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ 𝑁 = (pmSgn‘𝐷)    ⇒   ⊢ (𝐷 ∈ Fin → 𝑁 = (𝑥 ∈ 𝐵 ↦ (℩𝑠∃𝑤 ∈ Word 𝑇(𝑥 = (𝐺 Σg 𝑤) ∧ 𝑠 = (-1↑(♯‘𝑤))))))
Theorem	psgnvalfi 19585*	Value of the permutation sign function for permutations of finite sets. (Contributed by AV, 13-Jan-2019.)
⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝐵 = (Base‘𝐺)    &   ⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ 𝑁 = (pmSgn‘𝐷)    ⇒   ⊢ ((𝐷 ∈ Fin ∧ 𝑃 ∈ 𝐵) → (𝑁‘𝑃) = (℩𝑠∃𝑤 ∈ Word 𝑇(𝑃 = (𝐺 Σg 𝑤) ∧ 𝑠 = (-1↑(♯‘𝑤)))))
Theorem	psgnran 19586	The range of the permutation sign function for finite permutations. (Contributed by AV, 1-Jan-2019.)
⊢ 𝑃 = (Base‘(SymGrp‘𝑁))    &   ⊢ 𝑆 = (pmSgn‘𝑁)    ⇒   ⊢ ((𝑁 ∈ Fin ∧ 𝑄 ∈ 𝑃) → (𝑆‘𝑄) ∈ {1, -1})
Theorem	gsmtrcl 19587	The group sum of transpositions of a finite set is a permutation, see also psgneldm2i 19576. (Contributed by AV, 19-Jan-2019.)
⊢ 𝑆 = (SymGrp‘𝑁)    &   ⊢ 𝐵 = (Base‘𝑆)    &   ⊢ 𝑇 = ran (pmTrsp‘𝑁)    ⇒   ⊢ ((𝑁 ∈ Fin ∧ 𝑊 ∈ Word 𝑇) → (𝑆 Σg 𝑊) ∈ 𝐵)
Theorem	psgnfitr 19588*	A permutation of a finite set is generated by transpositions. (Contributed by AV, 13-Jan-2019.)
⊢ 𝐺 = (SymGrp‘𝑁)    &   ⊢ 𝐵 = (Base‘𝐺)    &   ⊢ 𝑇 = ran (pmTrsp‘𝑁)    ⇒   ⊢ (𝑁 ∈ Fin → (𝑄 ∈ 𝐵 ↔ ∃𝑤 ∈ Word 𝑇𝑄 = (𝐺 Σg 𝑤)))
Theorem	psgnfieu 19589*	A permutation of a finite set has exactly one parity. (Contributed by AV, 13-Jan-2019.)
⊢ 𝐺 = (SymGrp‘𝑁)    &   ⊢ 𝐵 = (Base‘𝐺)    &   ⊢ 𝑇 = ran (pmTrsp‘𝑁)    ⇒   ⊢ ((𝑁 ∈ Fin ∧ 𝑄 ∈ 𝐵) → ∃!𝑠∃𝑤 ∈ Word 𝑇(𝑄 = (𝐺 Σg 𝑤) ∧ 𝑠 = (-1↑(♯‘𝑤))))
Theorem	pmtrsn 19590	The value of the transposition generator function for a singleton is empty, i.e. there is no transposition for a singleton. This also holds for 𝐴 ∉ V, i.e. for the empty set {𝐴} = ∅ resulting in (pmTrsp‘∅) = ∅. (Contributed by AV, 6-Aug-2019.)
⊢ (pmTrsp‘{𝐴}) = ∅
Theorem	psgnsn 19591	The permutation sign function for a singleton. (Contributed by AV, 6-Aug-2019.)
⊢ 𝐷 = {𝐴}    &   ⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝐵 = (Base‘𝐺)    &   ⊢ 𝑁 = (pmSgn‘𝐷)    ⇒   ⊢ ((𝐴 ∈ 𝑉 ∧ 𝑋 ∈ 𝐵) → (𝑁‘𝑋) = 1)
Theorem	psgnprfval 19592*	The permutation sign function for a pair. (Contributed by AV, 10-Dec-2018.)
⊢ 𝐷 = {1, 2}    &   ⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝐵 = (Base‘𝐺)    &   ⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ 𝑁 = (pmSgn‘𝐷)    ⇒   ⊢ (𝑋 ∈ 𝐵 → (𝑁‘𝑋) = (℩𝑠∃𝑤 ∈ Word 𝑇(𝑋 = (𝐺 Σg 𝑤) ∧ 𝑠 = (-1↑(♯‘𝑤)))))
Theorem	psgnprfval1 19593	The permutation sign of the identity for a pair. (Contributed by AV, 11-Dec-2018.)
⊢ 𝐷 = {1, 2}    &   ⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝐵 = (Base‘𝐺)    &   ⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ 𝑁 = (pmSgn‘𝐷)    ⇒   ⊢ (𝑁‘{⟨1, 1⟩, ⟨2, 2⟩}) = 1
Theorem	psgnprfval2 19594	The permutation sign of the transposition for a pair. (Contributed by AV, 10-Dec-2018.)
⊢ 𝐷 = {1, 2}    &   ⊢ 𝐺 = (SymGrp‘𝐷)    &   ⊢ 𝐵 = (Base‘𝐺)    &   ⊢ 𝑇 = ran (pmTrsp‘𝐷)    &   ⊢ 𝑁 = (pmSgn‘𝐷)    ⇒   ⊢ (𝑁‘{⟨1, 2⟩, ⟨2, 1⟩}) = -1
10.2.11  p-Groups and Sylow groups; Sylow's theorems
Syntax	cod 19595	Extend class notation to include the order function on the elements of a group.
class od
Syntax	cgex 19596	Extend class notation to include the order function on the elements of a group.
class gEx
Syntax	cpgp 19597	Extend class notation to include the class of all p-groups.
class pGrp
Syntax	cslw 19598	Extend class notation to include the class of all Sylow p-subgroups of a group.
class pSyl
Definition	df-od 19599*	Define the order of an element in a group. (Contributed by Mario Carneiro, 13-Jul-2014.) (Revised by Stefan O'Rear, 4-Sep-2015.) (Revised by AV, 5-Oct-2020.)
⊢ od = (𝑔 ∈ V ↦ (𝑥 ∈ (Base‘𝑔) ↦ ⦋{𝑛 ∈ ℕ ∣ (𝑛(.g‘𝑔)𝑥) = (0g‘𝑔)} / 𝑖⦌if(𝑖 = ∅, 0, inf(𝑖, ℝ, < ))))
Definition	df-gex 19600*	Define the exponent of a group. (Contributed by Mario Carneiro, 13-Jul-2014.) (Revised by Stefan O'Rear, 4-Sep-2015.) (Revised by AV, 26-Sep-2020.)
⊢ gEx = (𝑔 ∈ V ↦ ⦋{𝑛 ∈ ℕ ∣ ∀𝑥 ∈ (Base‘𝑔)(𝑛(.g‘𝑔)𝑥) = (0g‘𝑔)} / 𝑖⦌if(𝑖 = ∅, 0, inf(𝑖, ℝ, < )))