Imports
/- Copyright (c) 2024 Joseph Tooby-Smith. All rights reserved. Released under Apache 2.0 license as described in the file LICENSE. Authors: Joseph Tooby-Smith -/ module public import Physlib.Mathematics.List.InsertIdx public import Mathlib.Tactic.FinCases public import Mathlib.Algebra.BigOperators.Group.Finset.Piecewise public import Mathlib.Data.Fintype.Card public import Mathlib.Algebra.FreeMonoid.Basic public import Mathlib.Data.List.Sort

Field statistics

Basic properties related to whether a field, or list of fields, is bosonic or fermionic.

@[expose] public section

The type FieldStatistic is the type containing two elements bosonic and fermionic. This type is used to specify if a field or operator obeys bosonic or fermionic statistics.

inductive FieldStatistic : Type where | bosonic : FieldStatistic | fermionic : FieldStatistic deriving DecidableEq

The type FieldStatistic carries an instance of a commutative group in which

    bosonic * bosonic = bosonic

    bosonic * fermionic = fermionic

    fermionic * bosonic = fermionic

    fermionic * fermionic = bosonic

This group is isomorphic to ℤ₂.

@[simp] instance : CommGroup FieldStatistic where one := bosonic mul a b := match a, b with | bosonic, bosonic => bosonic | bosonic, fermionic => fermionic | fermionic, bosonic => fermionic | fermionic, fermionic => bosonic inv a := a mul_assoc a b c := 𝓕:Typea:FieldStatisticb:FieldStatisticc:FieldStatistica * b * c = a * (b * c) 𝓕:Typeb:FieldStatisticc:FieldStatisticbosonic * b * c = bosonic * (b * c)𝓕:Typeb:FieldStatisticc:FieldStatisticfermionic * b * c = fermionic * (b * c) 𝓕:Typeb:FieldStatisticc:FieldStatisticbosonic * b * c = bosonic * (b * c)𝓕:Typeb:FieldStatisticc:FieldStatisticfermionic * b * c = fermionic * (b * c) 𝓕:Typec:FieldStatisticfermionic * bosonic * c = fermionic * (bosonic * c)𝓕:Typec:FieldStatisticfermionic * fermionic * c = fermionic * (fermionic * c) 𝓕:Typec:FieldStatisticbosonic * bosonic * c = bosonic * (bosonic * c)𝓕:Typec:FieldStatisticbosonic * fermionic * c = bosonic * (fermionic * c)𝓕:Typec:FieldStatisticfermionic * bosonic * c = fermionic * (bosonic * c)𝓕:Typec:FieldStatisticfermionic * fermionic * c = fermionic * (fermionic * c) 𝓕:Typefermionic * fermionic * bosonic = fermionic * (fermionic * bosonic)𝓕:Typefermionic * fermionic * fermionic = fermionic * (fermionic * fermionic) 𝓕:Typebosonic * bosonic * bosonic = bosonic * (bosonic * bosonic)𝓕:Typebosonic * bosonic * fermionic = bosonic * (bosonic * fermionic)𝓕:Typebosonic * fermionic * bosonic = bosonic * (fermionic * bosonic)𝓕:Typebosonic * fermionic * fermionic = bosonic * (fermionic * fermionic)𝓕:Typefermionic * bosonic * bosonic = fermionic * (bosonic * bosonic)𝓕:Typefermionic * bosonic * fermionic = fermionic * (bosonic * fermionic)𝓕:Typefermionic * fermionic * bosonic = fermionic * (fermionic * bosonic)𝓕:Typefermionic * fermionic * fermionic = fermionic * (fermionic * fermionic) All goals completed! 🐙 one_mul a := 𝓕:Typea:FieldStatistic1 * a = a 𝓕:Type1 * bosonic = bosonic𝓕:Type1 * fermionic = fermionic 𝓕:Type1 * bosonic = bosonic𝓕:Type1 * fermionic = fermionic All goals completed! 🐙 mul_one a := 𝓕:Typea:FieldStatistica * 1 = a 𝓕:Typebosonic * 1 = bosonic𝓕:Typefermionic * 1 = fermionic 𝓕:Typebosonic * 1 = bosonic𝓕:Typefermionic * 1 = fermionic All goals completed! 🐙 inv_mul_cancel a := 𝓕:Typea:FieldStatistica * a = 1 𝓕:Typebosonic * bosonic = 1𝓕:Typefermionic * fermionic = 1 𝓕:Typebosonic * bosonic = 1𝓕:Typefermionic * fermionic = 1 𝓕:Typebosonic = 1 𝓕:Typebosonic = 1𝓕:Typebosonic = 1 All goals completed! 🐙 mul_comm a b := 𝓕:Typea:FieldStatisticb:FieldStatistica * b = b * a 𝓕:Typeb:FieldStatisticbosonic * b = b * bosonic𝓕:Typeb:FieldStatisticfermionic * b = b * fermionic 𝓕:Typeb:FieldStatisticbosonic * b = b * bosonic𝓕:Typeb:FieldStatisticfermionic * b = b * fermionic 𝓕:Typefermionic * bosonic = bosonic * fermionic𝓕:Typefermionic * fermionic = fermionic * fermionic 𝓕:Typebosonic * bosonic = bosonic * bosonic𝓕:Typebosonic * fermionic = fermionic * bosonic𝓕:Typefermionic * bosonic = bosonic * fermionic𝓕:Typefermionic * fermionic = fermionic * fermionic All goals completed! 🐙
@[simp] lemma bosonic_mul_bosonic : bosonic * bosonic = bosonic := rfl@[simp] lemma bosonic_mul_fermionic : bosonic * fermionic = fermionic := rfl@[simp] lemma fermionic_mul_bosonic : fermionic * bosonic = fermionic := rfl@[simp] lemma fermionic_mul_fermionic : fermionic * fermionic = bosonic := rfl@[simp] lemma mul_bosonic (a : FieldStatistic) : a * bosonic = a := a:FieldStatistica * bosonic = a bosonic * bosonic = bosonicfermionic * bosonic = fermionic bosonic * bosonic = bosonicfermionic * bosonic = fermionic All goals completed! 🐙@[simp] lemma mul_self (a : FieldStatistic) : a * a = 1 := a:FieldStatistica * a = 1 bosonic * bosonic = 1fermionic * fermionic = 1 bosonic * bosonic = 1fermionic * fermionic = 1 All goals completed! 🐙

Field statics form a finite type.

instance : Fintype FieldStatistic where elems := {bosonic, fermionic} complete := 𝓕:Type (x : FieldStatistic), x {bosonic, fermionic} 𝓕:Typec:FieldStatisticc {bosonic, fermionic} 𝓕:Typebosonic {bosonic, fermionic}𝓕:Typefermionic {bosonic, fermionic} 𝓕:Typebosonic {bosonic, fermionic} All goals completed! 🐙 𝓕:Typefermionic {bosonic, fermionic} 𝓕:Type{fermionic, bosonic, fermionic} = {bosonic, fermionic} All goals completed! 🐙
@[simp] lemma fermionic_not_eq_bonsic : ¬ fermionic = bosonic := ¬fermionic = bosonic h:fermionic = bosonicFalse All goals completed! 🐙lemma bonsic_eq_fermionic_false : bosonic = fermionic false := bosonic = fermionic false = true All goals completed! 🐙@[simp] lemma neq_fermionic_iff_eq_bosonic (a : FieldStatistic) : ¬ a = fermionic a = bosonic := a:FieldStatistic¬a = fermionic a = bosonic ¬bosonic = fermionic bosonic = bosonic¬fermionic = fermionic fermionic = bosonic ¬bosonic = fermionic bosonic = bosonic All goals completed! 🐙 ¬fermionic = fermionic fermionic = bosonic All goals completed! 🐙@[simp] lemma neq_bosonic_iff_eq_fermionic (a : FieldStatistic) : ¬ a = bosonic a = fermionic := a:FieldStatistic¬a = bosonic a = fermionic ¬bosonic = bosonic bosonic = fermionic¬fermionic = bosonic fermionic = fermionic ¬bosonic = bosonic bosonic = fermionic All goals completed! 🐙 ¬fermionic = bosonic fermionic = fermionic All goals completed! 🐙@[simp] lemma bosonic_ne_iff_fermionic_eq (a : FieldStatistic) : ¬ bosonic = a fermionic = a := a:FieldStatistic¬bosonic = a fermionic = a ¬bosonic = bosonic fermionic = bosonic¬bosonic = fermionic fermionic = fermionic ¬bosonic = bosonic fermionic = bosonic All goals completed! 🐙 ¬bosonic = fermionic fermionic = fermionic All goals completed! 🐙@[simp] lemma fermionic_ne_iff_bosonic_eq (a : FieldStatistic) : ¬ fermionic = a bosonic = a := a:FieldStatistic¬fermionic = a bosonic = a ¬fermionic = bosonic bosonic = bosonic¬fermionic = fermionic bosonic = fermionic ¬fermionic = bosonic bosonic = bosonic All goals completed! 🐙 ¬fermionic = fermionic bosonic = fermionic All goals completed! 🐙lemma eq_self_if_eq_bosonic {a : FieldStatistic} : (if a = bosonic then bosonic else fermionic) = a := a:FieldStatistic(if a = bosonic then bosonic else fermionic) = a (if bosonic = bosonic then bosonic else fermionic) = bosonic(if fermionic = bosonic then bosonic else fermionic) = fermionic (if bosonic = bosonic then bosonic else fermionic) = bosonic(if fermionic = bosonic then bosonic else fermionic) = fermionic All goals completed! 🐙lemma eq_self_if_bosonic_eq {a : FieldStatistic} : (if bosonic = a then bosonic else fermionic) = a := a:FieldStatistic(if bosonic = a then bosonic else fermionic) = a (if bosonic = bosonic then bosonic else fermionic) = bosonic(if bosonic = fermionic then bosonic else fermionic) = fermionic (if bosonic = bosonic then bosonic else fermionic) = bosonic(if bosonic = fermionic then bosonic else fermionic) = fermionic All goals completed! 🐙lemma mul_eq_one_iff (a b : FieldStatistic) : a * b = 1 a = b := a:FieldStatisticb:FieldStatistica * b = 1 a = b b:FieldStatisticbosonic * b = 1 bosonic = bb:FieldStatisticfermionic * b = 1 fermionic = b b:FieldStatisticbosonic * b = 1 bosonic = bb:FieldStatisticfermionic * b = 1 fermionic = b fermionic * bosonic = 1 fermionic = bosonicfermionic * fermionic = 1 fermionic = fermionic bosonic * bosonic = 1 bosonic = bosonicbosonic * fermionic = 1 bosonic = fermionicfermionic * bosonic = 1 fermionic = bosonicfermionic * fermionic = 1 fermionic = fermionic All goals completed! 🐙lemma one_eq_mul_iff (a b : FieldStatistic) : 1 = a * b a = b := a:FieldStatisticb:FieldStatistic1 = a * b a = b b:FieldStatistic1 = bosonic * b bosonic = bb:FieldStatistic1 = fermionic * b fermionic = b b:FieldStatistic1 = bosonic * b bosonic = bb:FieldStatistic1 = fermionic * b fermionic = b 1 = fermionic * bosonic fermionic = bosonic1 = fermionic * fermionic fermionic = fermionic 1 = bosonic * bosonic bosonic = bosonic1 = bosonic * fermionic bosonic = fermionic1 = fermionic * bosonic fermionic = bosonic1 = fermionic * fermionic fermionic = fermionic All goals completed! 🐙lemma mul_eq_iff_eq_mul (a b c : FieldStatistic) : a * b = c a = b * c := a:FieldStatisticb:FieldStatisticc:FieldStatistica * b = c a = b * c b:FieldStatisticc:FieldStatisticbosonic * b = c bosonic = b * cb:FieldStatisticc:FieldStatisticfermionic * b = c fermionic = b * c b:FieldStatisticc:FieldStatisticbosonic * b = c bosonic = b * cb:FieldStatisticc:FieldStatisticfermionic * b = c fermionic = b * c c:FieldStatisticfermionic * bosonic = c fermionic = bosonic * cc:FieldStatisticfermionic * fermionic = c fermionic = fermionic * c c:FieldStatisticbosonic * bosonic = c bosonic = bosonic * cc:FieldStatisticbosonic * fermionic = c bosonic = fermionic * cc:FieldStatisticfermionic * bosonic = c fermionic = bosonic * cc:FieldStatisticfermionic * fermionic = c fermionic = fermionic * c fermionic * fermionic = bosonic fermionic = fermionic * bosonicfermionic * fermionic = fermionic fermionic = fermionic * fermionic bosonic * bosonic = bosonic bosonic = bosonic * bosonicbosonic * bosonic = fermionic bosonic = bosonic * fermionicbosonic * fermionic = bosonic bosonic = fermionic * bosonicbosonic * fermionic = fermionic bosonic = fermionic * fermionicfermionic * bosonic = bosonic fermionic = bosonic * bosonicfermionic * bosonic = fermionic fermionic = bosonic * fermionicfermionic * fermionic = bosonic fermionic = fermionic * bosonicfermionic * fermionic = fermionic fermionic = fermionic * fermionic All goals completed! 🐙 all_goals All goals completed! 🐙lemma mul_eq_iff_eq_mul' (a b c : FieldStatistic) : a * b = c b = a * c := a:FieldStatisticb:FieldStatisticc:FieldStatistica * b = c b = a * c b:FieldStatisticc:FieldStatisticbosonic * b = c b = bosonic * cb:FieldStatisticc:FieldStatisticfermionic * b = c b = fermionic * c b:FieldStatisticc:FieldStatisticbosonic * b = c b = bosonic * cb:FieldStatisticc:FieldStatisticfermionic * b = c b = fermionic * c c:FieldStatisticfermionic * bosonic = c bosonic = fermionic * cc:FieldStatisticfermionic * fermionic = c fermionic = fermionic * c c:FieldStatisticbosonic * bosonic = c bosonic = bosonic * cc:FieldStatisticbosonic * fermionic = c fermionic = bosonic * cc:FieldStatisticfermionic * bosonic = c bosonic = fermionic * cc:FieldStatisticfermionic * fermionic = c fermionic = fermionic * c fermionic * fermionic = bosonic fermionic = fermionic * bosonicfermionic * fermionic = fermionic fermionic = fermionic * fermionic bosonic * bosonic = bosonic bosonic = bosonic * bosonicbosonic * bosonic = fermionic bosonic = bosonic * fermionicbosonic * fermionic = bosonic fermionic = bosonic * bosonicbosonic * fermionic = fermionic fermionic = bosonic * fermionicfermionic * bosonic = bosonic bosonic = fermionic * bosonicfermionic * bosonic = fermionic bosonic = fermionic * fermionicfermionic * fermionic = bosonic fermionic = fermionic * bosonicfermionic * fermionic = fermionic fermionic = fermionic * fermionic All goals completed! 🐙 all_goals All goals completed! 🐙

The field statistics of a list of fields is fermionic if there is an odd number of fermions, otherwise it is bosonic.

def ofList (s : 𝓕 FieldStatistic) : (φs : List 𝓕) FieldStatistic | [] => bosonic | φ :: φs => if s φ = ofList s φs then bosonic else fermionic
𝓕:Types:𝓕 FieldStatisticφ:𝓕φs:List 𝓕ha: (a b : FieldStatistic), (if a = b then bosonic else fermionic) = a * bofList s (φ :: φs) = s φ * ofList s φs All goals completed! 🐙All goals completed! 🐙All goals completed! 🐙@[simp] lemma ofList_freeMonoid (s : 𝓕 FieldStatistic) (φ : 𝓕) : ofList s (FreeMonoid.of φ) = s φ := ofList_singleton s φ@[simp] lemma ofList_empty (s : 𝓕 FieldStatistic) : ofList s [] = bosonic := rfl𝓕:Types:𝓕 FieldStatisticφs':List 𝓕a:𝓕l:List 𝓕ih:ofList s (l ++ φs') = if ofList s l = ofList s φs' then bosonic else fermionichab: (a b c : FieldStatistic), (if a = if b = c then bosonic else fermionic then bosonic else fermionic) = if (if a = b then bosonic else fermionic) = c then bosonic else fermionicofList s (a :: l ++ φs') = if ofList s (a :: l) = ofList s φs' then bosonic else fermionic All goals completed! 🐙𝓕:Types:𝓕 FieldStatisticφs:List 𝓕φs':List 𝓕ha: (a b : FieldStatistic), (if a = b then bosonic else fermionic) = a * b(if ofList s φs = ofList s φs' then bosonic else fermionic) = ofList s φs * ofList s φs' All goals completed! 🐙𝓕:Types:𝓕 FieldStatisticl:List 𝓕l':List 𝓕h:l.Perm l'(List.map s l).prod = (List.map s l').prod All goals completed! 🐙lemma ofList_orderedInsert (s : 𝓕 FieldStatistic) (le1 : 𝓕 𝓕 Prop) [DecidableRel le1] (φs : List 𝓕) (φ : 𝓕) : ofList s (List.orderedInsert le1 φ φs) = ofList s (φ :: φs) := ofList_perm s (List.perm_orderedInsert le1 φ φs)@[simp] lemma ofList_insertionSort (s : 𝓕 FieldStatistic) (le1 : 𝓕 𝓕 Prop) [DecidableRel le1] (φs : List 𝓕) : ofList s (List.insertionSort le1 φs) = ofList s φs := ofList_perm s (List.perm_insertionSort le1 φs)𝓕:Types:𝓕 FieldStatisticφ:𝓕φs:List 𝓕i:Fin (φ :: φs).lengthl:List (Fin (φ :: φs).length)hl:(i :: l).Noduph1:s (φ :: φs)[i] = j, if j = i then s (φ :: φs)[i] else 1a:Fin (φ :: φs).lengthha:a = is (φ :: φs)[i] = s (φ :: φs)[i]𝓕:Types:𝓕 FieldStatisticφ:𝓕φs:List 𝓕i:Fin (φ :: φs).lengthl:List (Fin (φ :: φs).length)hl:(i :: l).Noduph1:s (φ :: φs)[i] = j, if j = i then s (φ :: φs)[i] else 1a:Fin (φ :: φs).lengthha:a = ii l 𝓕:Types:𝓕 FieldStatisticφ:𝓕φs:List 𝓕i:Fin (φ :: φs).lengthl:List (Fin (φ :: φs).length)hl:(i :: l).Noduph1:s (φ :: φs)[i] = j, if j = i then s (φ :: φs)[i] else 1a:Fin (φ :: φs).lengthha:a = ii l 𝓕:Types:𝓕 FieldStatisticφ:𝓕φs:List 𝓕i:Fin (φ :: φs).lengthl:List (Fin (φ :: φs).length)h1:s (φ :: φs)[i] = j, if j = i then s (φ :: φs)[i] else 1a:Fin (φ :: φs).lengthha:a = ihl:i l l.Nodupi l All goals completed! 🐙 𝓕:Types:𝓕 FieldStatisticφ:𝓕φs:List 𝓕i:Fin (φ :: φs).lengthl:List (Fin (φ :: φs).length)hl:(i :: l).Noduph1:s (φ :: φs)[i] = j, if j = i then s (φ :: φs)[i] else 1a:Fin (φ :: φs).lengthha:¬a = i(if a l then if a = i then s (φ :: φs)[i] * s (φ :: φs)[a] else s (φ :: φs)[a] else if a = i then s (φ :: φs)[i] else 1) = if a = i a l then s (φ :: φs)[a] else 1 𝓕:Types:𝓕 FieldStatisticφ:𝓕φs:List 𝓕i:Fin (φ :: φs).lengthl:List (Fin (φ :: φs).length)hl:(i :: l).Noduph1:s (φ :: φs)[i] = j, if j = i then s (φ :: φs)[i] else 1a:Fin (φ :: φs).lengthha:¬a = i(if a l then s (φ :: φs)[a] else 1) = if a l then s (φ :: φs)[a] else 1 All goals completed! 🐙 𝓕:Types:𝓕 FieldStatisticφ:𝓕φs:List 𝓕i:Fin (φ :: φs).lengthl:List (Fin (φ :: φs).length)hl:i l l.Nodupl.Nodup All goals completed! 🐙All goals completed! 🐙

ofList and take

All goals completed! 🐙All goals completed! 🐙lemma ofList_take_zero (φs : List 𝓕) : ofList q (List.take 0 φs) = 1 := 𝓕:Typeq:𝓕 FieldStatisticφs:List 𝓕ofList q (List.take 0 φs) = 1 𝓕:Typeq:𝓕 FieldStatisticφs:List 𝓕bosonic = 1 All goals completed! 🐙All goals completed! 🐙All goals completed! 🐙lemma ofList_insert_lt_eq (n m : ) (φ1 : 𝓕) (φs : List 𝓕) (hn : m n) (hm : m φs.length) : ofList q ((List.insertIdx φs m φ1).take (n + 1)) = ofList q ((φ1 :: φs).take (n + 1)) := 𝓕:Typeq:𝓕 FieldStatisticn:m:φ1:𝓕φs:List 𝓕hn:m nhm:m φs.lengthofList q (List.take (n + 1) (φs.insertIdx m φ1)) = ofList q (List.take (n + 1) (φ1 :: φs)) 𝓕:Typeq:𝓕 FieldStatisticn:m:φ1:𝓕φs:List 𝓕hn:m nhm:m φs.length(List.take (n + 1) (φs.insertIdx m φ1)).Perm (List.take (n + 1) (φ1 :: φs)) 𝓕:Typeq:𝓕 FieldStatisticn:m:φ1:𝓕φs:List 𝓕hn:m nhm:m φs.length(List.take (n + 1) (φs.insertIdx m φ1)).Perm (φ1 :: List.take n φs) All goals completed! 🐙𝓕:Typeq:𝓕 FieldStatisticn:m:φ1:𝓕φs:List 𝓕hn:m nhm:m φs.lengthm n𝓕:Typeq:𝓕 FieldStatisticn:m:φ1:𝓕φs:List 𝓕hn:m nhm:m φs.lengthm φs.length 𝓕:Typeq:𝓕 FieldStatisticn:m:φ1:𝓕φs:List 𝓕hn:m nhm:m φs.lengthm n All goals completed! 🐙 𝓕:Typeq:𝓕 FieldStatisticn:m:φ1:𝓕φs:List 𝓕hn:m nhm:m φs.lengthm φs.length All goals completed! 🐙

The instance of an additive monoid on FieldStatistic.

All goals completed! 🐙 nsmul_succ a n := 𝓕:Typeq:𝓕 FieldStatistica:n:FieldStatistic(a + 1) n = a n + n 𝓕:Typeq:𝓕 FieldStatistica:n:FieldStatistic _i, n = (∏ _i, n) * n All goals completed! 🐙
@[simp] lemma add_eq_mul (a b : FieldStatistic) : a + b = a * b := rfl