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Physlib.QFT.PerturbationTheory.FieldStatistics.Basic

42 declarations

inductive

Quantum field statistics (bosonic vs. fermionic)

#FieldStatistic

The type FieldStatistic\text{FieldStatistic} is an inductive type consisting of exactly two elements: bosonic\text{bosonic} and fermionic\text{fermionic}. It is used to categorize whether a physical field or operator obeys Bose-Einstein statistics (bosonic) or Fermi-Dirac statistics (fermionic).

instance

Decidability of s1=s2s_1 = s_2 for field statistics

#instDecidableEqFieldStatistic

For any two field statistics s1,s2FieldStatistics_1, s_2 \in \text{FieldStatistic}, it is decidable whether s1=s2s_1 = s_2. This means there exists an algorithmic procedure to determine if two given statistics are both bosonic\text{bosonic}, both fermionic\text{fermionic}, or different.

instance

Commutative group structure on field statistics (Z2\cong \mathbb{Z}_2)

#instCommGroup

The type FieldStatistic\text{FieldStatistic} forms a commutative group where the identity element is bosonic\text{bosonic}. The group operation \cdot follows the rules of parity: - bosonicbosonic=bosonic\text{bosonic} \cdot \text{bosonic} = \text{bosonic} - bosonicfermionic=fermionic\text{bosonic} \cdot \text{fermionic} = \text{fermionic} - fermionicbosonic=fermionic\text{fermionic} \cdot \text{bosonic} = \text{fermionic} - fermionicfermionic=bosonic\text{fermionic} \cdot \text{fermionic} = \text{bosonic} In this structure, every element is its own inverse, and the group is isomorphic to Z2\mathbb{Z}_2.

theorem

bosonicbosonic=bosonic\text{bosonic} \cdot \text{bosonic} = \text{bosonic}

#bosonic_mul_bosonic

In the commutative group of quantum field statistics (FieldStatistic\text{FieldStatistic}), where bosonic\text{bosonic} is the identity element, the product of a bosonic statistic with itself is a bosonic statistic. That is: bosonicbosonic=bosonic\text{bosonic} \cdot \text{bosonic} = \text{bosonic}

theorem

bosonicfermionic=fermionic\text{bosonic} \cdot \text{fermionic} = \text{fermionic}

#bosonic_mul_fermionic

In the commutative group of quantum field statistics (FieldStatistic\text{FieldStatistic}), where the identity element is bosonic\text{bosonic} and the non-trivial element is fermionic\text{fermionic}, the product of a bosonic statistic and a fermionic statistic is a fermionic statistic. That is: bosonicfermionic=fermionic\text{bosonic} \cdot \text{fermionic} = \text{fermionic}

theorem

fermionicbosonic=fermionic\text{fermionic} \cdot \text{bosonic} = \text{fermionic}

#fermionic_mul_bosonic

In the commutative group of quantum field statistics (FieldStatistic\text{FieldStatistic}), where the identity element is bosonic\text{bosonic} and the non-trivial element is fermionic\text{fermionic}, the product of a fermionic statistic and a bosonic statistic is a fermionic statistic. That is: fermionicbosonic=fermionic\text{fermionic} \cdot \text{bosonic} = \text{fermionic}

theorem

fermionicfermionic=bosonic\text{fermionic} \cdot \text{fermionic} = \text{bosonic}

#fermionic_mul_fermionic

In the commutative group of field statistics (FieldStatistic\text{FieldStatistic}), the product of two fermionic statistics is a bosonic statistic. This reflects the Z2\mathbb{Z}_2 parity structure where the combination of two odd (fermionic) elements results in an even (bosonic) element: fermionicfermionic=bosonic\text{fermionic} \cdot \text{fermionic} = \text{bosonic}

theorem

abosonic=aa \cdot \text{bosonic} = a

#mul_bosonic

In the commutative group of quantum field statistics FieldStatistic\text{FieldStatistic}, which classifies fields as either bosonic\text{bosonic} or fermionic\text{fermionic}, the product of any statistic aa with the bosonic\text{bosonic} statistic is equal to aa: abosonic=aa \cdot \text{bosonic} = a This confirms that the bosonic\text{bosonic} statistic acts as the identity element within this group structure.

theorem

aa=1a \cdot a = 1 for any field statistic aa

#mul_self

For any field statistic aFieldStatistica \in \text{FieldStatistic}, the product of aa with itself is the identity element 11 of the commutative group of field statistics, i.e., aa=1a \cdot a = 1. This identity element 11 corresponds to the bosonic statistic.

instance

FieldStatistic\text{FieldStatistic} is a finite type

#instFintype

The type FieldStatistic\text{FieldStatistic}, which classifies quantum fields as either bosonic\text{bosonic} or fermionic\text{fermionic}, is a finite type (an instance of `Fintype`). It consists of exactly two distinct elements: {bosonic,fermionic}\{\text{bosonic}, \text{fermionic}\}.

theorem

fermionicbosonic\text{fermionic} \neq \text{bosonic}

#fermionic_not_eq_bonsic

The field statistics fermionic\text{fermionic} and bosonic\text{bosonic} are not equal, i.e., fermionicbosonic\text{fermionic} \neq \text{bosonic}.

theorem

bosonicfermionic\text{bosonic} \neq \text{fermionic}

#bonsic_eq_fermionic_false

The equality between the field statistics bosonic\text{bosonic} and fermionic\text{fermionic} is equivalent to False\text{False}.

theorem

afermionic    a=bosonica \neq \text{fermionic} \iff a = \text{bosonic}

#neq_fermionic_iff_eq_bosonic

For any quantum field statistic aFieldStatistica \in \text{FieldStatistic}, aa is not fermionic if and only if aa is bosonic. Here, FieldStatistic\text{FieldStatistic} is the type classifying fields as either bosonic\text{bosonic} or fermionic\text{fermionic}.

theorem

abosonic    a=fermionica \neq \text{bosonic} \iff a = \text{fermionic}

#neq_bosonic_iff_eq_fermionic

For any field statistic aFieldStatistica \in \text{FieldStatistic}, it holds that abosonica \neq \text{bosonic} if and only if a=fermionica = \text{fermionic}.

theorem

bosonica    fermionic=a\text{bosonic} \neq a \iff \text{fermionic} = a

#bosonic_ne_iff_fermionic_eq

For any field statistic aFieldStatistica \in \text{FieldStatistic}, the condition that aa is not bosonic is equivalent to the condition that aa is fermionic. In mathematical notation, bosonica    fermionic=a\text{bosonic} \neq a \iff \text{fermionic} = a.

theorem

fermionica    bosonic=a\text{fermionic} \neq a \iff \text{bosonic} = a

#fermionic_ne_iff_bosonic_eq

For any field statistic aa, it holds that aa is not equal to fermionic\text{fermionic} if and only if aa is equal to bosonic\text{bosonic}. In mathematical terms, for aFieldStatistica \in \text{FieldStatistic}, fermionica    bosonic=a\text{fermionic} \neq a \iff \text{bosonic} = a.

theorem

ab=1    a=ba \cdot b = 1 \iff a = b for field statistics

#mul_eq_one_iff

For any quantum field statistics a,bFieldStatistica, b \in \text{FieldStatistic}, the product aba \cdot b is equal to the identity element 11 (the bosonic\text{bosonic} statistic) if and only if a=ba = b. The type FieldStatistic\text{FieldStatistic} classifies fields as either bosonic\text{bosonic} or fermionic\text{fermionic} and forms a commutative group where every element is its own inverse.

theorem

1=ab    a=b1 = a \cdot b \iff a = b for field statistics

#one_eq_mul_iff

In the commutative group of quantum field statistics FieldStatistic\text{FieldStatistic} (where elements are either bosonic\text{bosonic} or fermionic\text{fermionic}), the product of two statistics aa and bb is the identity element 11 (the bosonic\text{bosonic} statistic) if and only if aa and bb are equal.

theorem

ab=c    a=bca \cdot b = c \iff a = b \cdot c for field statistics

#mul_eq_iff_eq_mul

For any quantum field statistics a,b,cFieldStatistica, b, c \in \text{FieldStatistic}, the product ab=ca \cdot b = c if and only if a=bca = b \cdot c. Here, FieldStatistic\text{FieldStatistic} is the type classifying fields as either bosonic\text{bosonic} or fermionic\text{fermionic}, forming a commutative group where the identity element is bosonic\text{bosonic} and every element is its own inverse (bb=bosonicb \cdot b = \text{bosonic}).

theorem

ab=c    b=aca \cdot b = c \iff b = a \cdot c for field statistics

#mul_eq_iff_eq_mul'

For any quantum field statistics a,b,cFieldStatistica, b, c \in \text{FieldStatistic}, the product ab=ca \cdot b = c holds if and only if b=acb = a \cdot c. Here, FieldStatistic\text{FieldStatistic} is the type classifying fields as either bosonic or fermionic, forming a commutative group where the identity element is bosonic and every element is its own inverse (i.e., xx=bosonicx \cdot x = \text{bosonic} for any statistic xx).

definition

Field statistic of a list of fields [ϕ1,,ϕn][\phi_1, \dots, \phi_n]

#ofList

Given a mapping s:FFieldStatistics: \mathcal{F} \to \text{FieldStatistic} that assigns a statistic (either bosonic\text{bosonic} or fermionic\text{fermionic}) to each field in a collection F\mathcal{F}, the function determines the collective statistic of a finite list of fields [ϕ1,ϕ2,,ϕn][\phi_1, \phi_2, \dots, \phi_n]. The resulting statistic is fermionic\text{fermionic} if there is an odd number of fields in the list for which s(ϕi)=fermionics(\phi_i) = \text{fermionic}; otherwise, the result is bosonic\text{bosonic}. Mathematically, this corresponds to the product i=1ns(ϕi)\prod_{i=1}^n s(\phi_i) where the statistics follow the group rules of Z2\mathbb{Z}_2.

theorem

ofList(s,ϕ::ϕs)=s(ϕ)ofList(s,ϕs)\text{ofList}(s, \phi :: \phi s) = s(\phi) \cdot \text{ofList}(s, \phi s)

#ofList_cons_eq_mul

Let s:FFieldStatistics: \mathcal{F} \to \text{FieldStatistic} be a mapping that assigns a statistic (either bosonic\text{bosonic} or fermionic\text{fermionic}) to each field in a collection F\mathcal{F}. For any field ϕF\phi \in \mathcal{F} and any finite list of fields ϕs\phi s, the collective statistic of the list formed by prepending ϕ\phi to ϕs\phi s (denoted ϕ::ϕs\phi :: \phi s) is equal to the product of the statistic of ϕ\phi and the collective statistic of the original list ϕs\phi s: ofList(s,ϕ::ϕs)=s(ϕ)ofList(s,ϕs)\text{ofList}(s, \phi :: \phi s) = s(\phi) \cdot \text{ofList}(s, \phi s) where the multiplication \cdot follows the Z2\mathbb{Z}_2 group structure of FieldStatistic\text{FieldStatistic} (where bosonic\text{bosonic} is the identity and fermionicfermionic=bosonic\text{fermionic} \cdot \text{fermionic} = \text{bosonic}).

theorem

ofList(s,ϕs)=ϕϕss(ϕ)\text{ofList}(s, \phi s) = \prod_{\phi \in \phi s} s(\phi)

#ofList_eq_prod

Let F\mathcal{F} be a collection of fields and s:FFieldStatistics: \mathcal{F} \to \text{FieldStatistic} be a mapping that assigns a statistic (bosonic or fermionic) to each field. For any list of fields ϕs=[ϕ1,ϕ2,,ϕn]\phi s = [\phi_1, \phi_2, \dots, \phi_n], the collective statistic ofList(s,ϕs)\text{ofList}(s, \phi s) is equal to the product of the statistics of the individual fields in the list: ofList(s,ϕs)=i=1ns(ϕi)\text{ofList}(s, \phi s) = \prod_{i=1}^n s(\phi_i) where the product is taken in the commutative group structure of FieldStatistic\text{FieldStatistic} (with bosonic\text{bosonic} as the identity).

theorem

The statistic of a singleton list [ϕ][\phi] equals s(ϕ)s(\phi)

#ofList_singleton

Given a collection of fields F\mathcal{F} and a mapping s:FFieldStatistics: \mathcal{F} \to \text{FieldStatistic} that assigns a statistic (bosonic or fermionic) to each field, the collective statistic of a singleton list containing exactly one field ϕF\phi \in \mathcal{F} is equal to the statistic of that field, s(ϕ)s(\phi).

theorem

ofList(s,FreeMonoid.of(ϕ))=s(ϕ)\text{ofList}(s, \text{FreeMonoid.of}(\phi)) = s(\phi)

#ofList_freeMonoid

Let F\mathcal{F} be a collection of fields and s:FFieldStatistics: \mathcal{F} \to \text{FieldStatistic} be a mapping that assigns a statistic (either bosonic\text{bosonic} or fermionic\text{fermionic}) to each field. For any field ϕF\phi \in \mathcal{F}, the collective field statistic of the field when represented as a single-element word in the free monoid, denoted by FreeMonoid.of(ϕ)\text{FreeMonoid.of}(\phi), is equal to the statistic of the individual field s(ϕ)s(\phi).

theorem

The collective statistic of an empty list is bosonic\text{bosonic}

#ofList_empty

Given a mapping s:FFieldStatistics : \mathcal{F} \to \text{FieldStatistic} that assigns a statistic (either bosonic\text{bosonic} or fermionic\text{fermionic}) to each field in a collection F\mathcal{F}, the collective field statistic of an empty list of fields is bosonic\text{bosonic}.

theorem

The collective statistic of concatenated lists is bosonic if and only if the individual lists have equal statistics

#ofList_append

Given a mapping s:FFieldStatistics: \mathcal{F} \to \text{FieldStatistic} that assigns a statistic (either bosonic\text{bosonic} or fermionic\text{fermionic}) to each field, the collective statistic of the concatenation of two lists of fields ϕs\phi s and ϕs\phi s' is bosonic\text{bosonic} if the collective statistics of the individual lists ϕs\phi s and ϕs\phi s' are equal, and fermionic\text{fermionic} otherwise.

theorem

ofList(s,φs+ ⁣+φs)=ofList(s,φs)ofList(s,φs)\text{ofList}(s, \varphi s \mathbin{+\!+} \varphi s') = \text{ofList}(s, \varphi s) \cdot \text{ofList}(s, \varphi s')

#ofList_append_eq_mul

Let s:FFieldStatistics: \mathcal{F} \to \text{FieldStatistic} be a mapping that assigns a statistic (either bosonic\text{bosonic} or fermionic\text{fermionic}) to each field in a collection F\mathcal{F}. For any two finite lists of fields φs\varphi s and φs\varphi s', the collective field statistic of their concatenation φs+ ⁣+φs\varphi s \mathbin{+\!+} \varphi s' is equal to the product of the collective statistics of the individual lists: ofList(s,φs+ ⁣+φs)=ofList(s,φs)ofList(s,φs)\text{ofList}(s, \varphi s \mathbin{+\!+} \varphi s') = \text{ofList}(s, \varphi s) \cdot \text{ofList}(s, \varphi s') where the multiplication \cdot follows the rules of the FieldStatistic\text{FieldStatistic} commutative group (isomorphic to Z2\mathbb{Z}_2), where bosonic\text{bosonic} is the identity element.

theorem

The Collective Field Statistic is Invariant Under Permutation of Fields

#ofList_perm

Let s:FFieldStatistics: \mathcal{F} \to \text{FieldStatistic} be a mapping that assigns a field statistic (either bosonic\text{bosonic} or fermionic\text{fermionic}) to each field in a collection F\mathcal{F}. For any two lists of fields ll and ll', if ll is a permutation of ll', then their collective field statistics are equal: ofList(s,l)=ofList(s,l)\text{ofList}(s, l) = \text{ofList}(s, l') This property arises because the collective statistic is calculated as the product of individual statistics within a commutative group.

theorem

ofList(s,orderedInsert φ φs)=ofList(s,φ::φs)\text{ofList}(s, \text{orderedInsert } \varphi \text{ } \varphi s) = \text{ofList}(s, \varphi :: \varphi s)

#ofList_orderedInsert

Let s:FFieldStatistics: \mathcal{F} \to \text{FieldStatistic} be a mapping that assigns a statistic (either bosonic\text{bosonic} or fermionic\text{fermionic}) to each field in a collection F\mathcal{F}. For any list of fields φs\varphi s, field φF\varphi \in \mathcal{F}, and decidable ordering relation \le on F\mathcal{F}, the collective field statistic of the list obtained by performing an ordered insertion of φ\varphi into φs\varphi s is equal to the collective statistic of the list formed by prepending φ\varphi to the front of φs\varphi s: ofList(s,orderedInsert(,φ,φs))=ofList(s,φ::φs)\text{ofList}(s, \text{orderedInsert}(\le, \varphi, \varphi s)) = \text{ofList}(s, \varphi :: \varphi s)

theorem

Insertion Sort Preserves the Collective Field Statistic

#ofList_insertionSort

Let s:FFieldStatistics: \mathcal{F} \to \text{FieldStatistic} be a mapping that assigns a statistic (either bosonic\text{bosonic} or fermionic\text{fermionic}) to each field in a collection F\mathcal{F}. For any list of fields ϕs\phi_s and any decidable binary relation \le on F\mathcal{F}, the collective field statistic of the list sorted via the insertion sort algorithm is equal to the collective field statistic of the original list: ofList(s,insertionSort(,ϕs))=ofList(s,ϕs)\text{ofList}(s, \text{insertionSort}(\le, \phi_s)) = \text{ofList}(s, \phi_s) This result follows from the fact that insertion sort is a permutation of the original list, and the collective statistic (defined as the product of individual statistics in a commutative Z2\mathbb{Z}_2 group) is invariant under permutations.

theorem

Collective statistic of sub-selected fields as a finite product over indices

#ofList_map_eq_finset_prod

Let s:FFieldStatistics: \mathcal{F} \to \text{FieldStatistic} be a mapping that assigns a statistic to each field. For any list of fields ϕs\phi_s and any list of indices ll into ϕs\phi_s such that ll contains no duplicate indices, the collective statistic of the list of fields selected by ll is equal to the product over all indices i{0,,length(ϕs)1}i \in \{0, \dots, \text{length}(\phi_s) - 1\} of s(ϕs[i])s(\phi_s[i]) if ili \in l, and the bosonic statistic (the identity 11) otherwise. Mathematically: ofList s(map ϕs l)=i=0length(ϕs)1{s(ϕs[i])if ilbosonicotherwise \text{ofList } s (\text{map } \phi_s \text{ } l) = \prod_{i=0}^{\text{length}(\phi_s)-1} \begin{cases} s(\phi_s[i]) & \text{if } i \in l \\ \text{bosonic} & \text{otherwise} \end{cases} where the map operation constructs a new list of fields by selecting elements from ϕs\phi_s at the indices specified in ll.

theorem

ofList(s,[ϕ1,ϕ2])=s(ϕ1)s(ϕ2)\text{ofList}(s, [\phi_1, \phi_2]) = s(\phi_1) \cdot s(\phi_2)

#ofList_pair

Let s:FFieldStatistics: \mathcal{F} \to \text{FieldStatistic} be a mapping that assigns a statistic (either bosonic\text{bosonic} or fermionic\text{fermionic}) to each field in a collection F\mathcal{F}. For any two fields ϕ1,ϕ2F\phi_1, \phi_2 \in \mathcal{F}, the collective field statistic of the list containing these two fields is equal to the product of their individual statistics: ofList(s,[ϕ1,ϕ2])=s(ϕ1)s(ϕ2) \text{ofList}(s, [\phi_1, \phi_2]) = s(\phi_1) \cdot s(\phi_2) where the multiplication \cdot follows the Z2\mathbb{Z}_2 commutative group structure of FieldStatistic\text{FieldStatistic} (with bosonic\text{bosonic} as the identity element).

theorem

The collective statistic ofList(take n ϕs)\text{ofList}(\text{take } n \text{ } \phi_s) is invariant under field insertion at index nn

#ofList_take_insert

Given a mapping q:FFieldStatisticq: \mathcal{F} \to \text{FieldStatistic} that assigns a statistic (either bosonic\text{bosonic} or fermionic\text{fermionic}) to each field, let ϕs\phi_s be a list of fields and nn be a natural number. The collective field statistic of the first nn elements of ϕs\phi_s is equal to the collective field statistic of the first nn elements of the list obtained by inserting a field ϕ\phi into ϕs\phi_s at index nn. Mathematically, this is expressed as: ofList q(take n ϕs)=ofList q(take n (insertIdx ϕs n ϕ)) \text{ofList } q (\text{take } n \text{ } \phi_s) = \text{ofList } q (\text{take } n \text{ } (\text{insertIdx } \phi_s \text{ } n \text{ } \phi)) where take n\text{take } n denotes the sublist of the first nn elements and insertIdx\text{insertIdx} denotes the insertion of an element at a specific position.

theorem

The field statistic of the first nn elements is invariant under erasing the nn-th element

#ofList_take_eraseIdx

Let F\mathcal{F} be a collection of fields and q:FFieldStatisticq: \mathcal{F} \to \text{FieldStatistic} be a mapping that assigns a statistic (either bosonic\text{bosonic} or fermionic\text{fermionic}) to each field. For any list of fields φs\varphi_s and any natural number nn, the collective field statistic of the first nn elements of the list remains unchanged if the element at index nn is removed from φs\varphi_s. That is, ofList(q,take(n,eraseIdx(n,φs)))=ofList(q,take(n,φs)) \text{ofList}(q, \text{take}(n, \text{eraseIdx}(n, \varphi_s))) = \text{ofList}(q, \text{take}(n, \varphi_s)) where take(n,L)\text{take}(n, L) returns the first nn elements of a list LL, and eraseIdx(n,L)\text{eraseIdx}(n, L) removes the element at the nn-th position.

theorem

The collective statistic of the first 00 fields is 11 (bosonic)

#ofList_take_zero

For any list of fields φs\varphi_s and any mapping q:FFieldStatisticq: \mathcal{F} \to \text{FieldStatistic} that assigns a statistic to each field, the collective field statistic of the first 00 elements of φs\varphi_s is the identity element 11 (which represents the bosonic statistic). Mathematically, this is expressed as: ofList q(take 0 φs)=1 \text{ofList } q (\text{take } 0 \text{ } \varphi_s) = 1 where take 0\text{take } 0 denotes the sublist containing the first zero elements (the empty list).

theorem

ofList(q,take(n+1,ϕ1::ϕs))=q(ϕ1)ofList(q,take(n,ϕs))\text{ofList}(q, \text{take}(n + 1, \phi_1 :: \phi s)) = q(\phi_1) \cdot \text{ofList}(q, \text{take}(n, \phi s))

#ofList_take_succ_cons

Let q:FFieldStatisticq : \mathcal{F} \to \text{FieldStatistic} be a mapping that assigns a statistic (either bosonic or fermionic) to each field in a collection F\mathcal{F}. For any natural number nn, field ϕ1F\phi_1 \in \mathcal{F}, and list of fields ϕs\phi s, the collective field statistic of the first n+1n+1 elements of the list formed by prepending ϕ1\phi_1 to ϕs\phi s is equal to the product of the statistic of ϕ1\phi_1 and the collective field statistic of the first nn elements of ϕs\phi s. Mathematically: ofList(q,take(n+1,ϕ1::ϕs))=q(ϕ1)ofList(q,take(n,ϕs)) \text{ofList}(q, \text{take}(n + 1, \phi_1 :: \phi s)) = q(\phi_1) \cdot \text{ofList}(q, \text{take}(n, \phi s)) where take(k,L)\text{take}(k, L) denotes the sublist of the first kk elements of LL, and the multiplication \cdot follows the Z2\mathbb{Z}_2 group structure of field statistics.

theorem

The field statistic of the first nn elements is invariant under insertion at index m>nm > n

#ofList_take_insertIdx_gt

Let q:FFieldStatisticq : \mathcal{F} \to \text{FieldStatistic} be a mapping that assigns a statistic (either bosonic or fermionic) to each field in a collection F\mathcal{F}. For any list of fields ϕs\phi_s, any field ϕ1F\phi_1 \in \mathcal{F}, and any natural numbers nn and mm such that n<mn < m, the collective field statistic of the first nn elements of the list obtained by inserting ϕ1\phi_1 into ϕs\phi_s at index mm is equal to the collective field statistic of the first nn elements of the original list ϕs\phi_s.

theorem

The collective statistic of a sublist is invariant under the insertion position of a field within that sublist

#ofList_insert_lt_eq

Let q:FFieldStatisticq : \mathcal{F} \to \text{FieldStatistic} be a mapping that assigns a statistic (either bosonic\text{bosonic} or fermionic\text{fermionic}) to each field in a collection F\mathcal{F}. For any list of fields ϕs\phi_s, a field ϕ1F\phi_1 \in \mathcal{F}, and natural numbers nn and mm such that mnm \leq n and mm is within the bounds of the list (mlength(ϕs)m \leq \text{length}(\phi_s)), the collective field statistic of the first n+1n + 1 elements of the list obtained by inserting ϕ1\phi_1 into ϕs\phi_s at index mm is equal to the collective field statistic of the first n+1n + 1 elements of the list obtained by prepending ϕ1\phi_1 to the front of ϕs\phi_s. Mathematically: ofList(q,take(n+1,insertIdx(ϕs,m,ϕ1)))=ofList(q,take(n+1,ϕ1::ϕs)) \text{ofList}(q, \text{take}(n + 1, \text{insertIdx}(\phi_s, m, \phi_1))) = \text{ofList}(q, \text{take}(n + 1, \phi_1 :: \phi_s)) where insertIdx(L,i,x)\text{insertIdx}(L, i, x) denotes the insertion of element xx into list LL at position ii, and take(k,L)\text{take}(k, L) denotes the sublist consisting of the first kk elements of LL.

theorem

ofList(q,take(n+1,insertIdx(ϕs,m,ϕ1)))=q(ϕ1)ofList(q,take(n,ϕs))\text{ofList}(q, \text{take}(n + 1, \text{insertIdx}(\phi_s, m, \phi_1))) = q(\phi_1) \cdot \text{ofList}(q, \text{take}(n, \phi_s)) for mnm \leq n

#ofList_take_insertIdx_le

Let q:FFieldStatisticq : \mathcal{F} \to \text{FieldStatistic} be a mapping that assigns a statistic (either bosonic\text{bosonic} or fermionic\text{fermionic}) to each field in a collection F\mathcal{F}. For any list of fields ϕs\phi_s, a field ϕ1F\phi_1 \in \mathcal{F}, and natural numbers nn and mm such that mnm \leq n and mm is within the bounds of the list (mlength(ϕs)m \leq \text{length}(\phi_s)), the collective field statistic of the first n+1n + 1 elements of the list obtained by inserting ϕ1\phi_1 into ϕs\phi_s at index mm is equal to the product of the statistic of ϕ1\phi_1 and the collective field statistic of the first nn elements of the original list ϕs\phi_s. Mathematically: ofList(q,take(n+1,insertIdx(ϕs,m,ϕ1)))=q(ϕ1)ofList(q,take(n,ϕs)) \text{ofList}(q, \text{take}(n + 1, \text{insertIdx}(\phi_s, m, \phi_1))) = q(\phi_1) \cdot \text{ofList}(q, \text{take}(n, \phi_s)) where insertIdx(L,i,x)\text{insertIdx}(L, i, x) denotes the insertion of element xx into list LL at position ii, take(k,L)\text{take}(k, L) denotes the sublist consisting of the first kk elements of LL, and the multiplication \cdot follows the Z2\mathbb{Z}_2 group structure of field statistics.

instance

Additive monoid structure on FieldStatistic\text{FieldStatistic} (bosonic=0\text{bosonic} = 0)

#instAddMonoid

The type FieldStatistic\text{FieldStatistic} is endowed with an additive monoid structure. In this structure, the additive identity element (zero) is bosonic\text{bosonic}. The addition of two statistics a+ba + b is defined to be equal to their multiplication aba \cdot b in the underlying commutative group. Specifically, the addition follows parity rules: - bosonic+bosonic=bosonic\text{bosonic} + \text{bosonic} = \text{bosonic} - bosonic+fermionic=fermionic\text{bosonic} + \text{fermionic} = \text{fermionic} - fermionic+fermionic=bosonic\text{fermionic} + \text{fermionic} = \text{bosonic} For any natural number nNn \in \mathbb{N} and statistic aa, the natural scalar multiplication nan \cdot a is defined as the nn-fold sum of aa, which corresponds to the product i=1na\prod_{i=1}^n a.

theorem

a+b=aba + b = a \cdot b for field statistics

#add_eq_mul

For any two field statistics a,bFieldStatistica, b \in \text{FieldStatistic} (which can be either bosonic or fermionic), the sum a+ba + b in the additive monoid is equal to the product aba \cdot b in the commutative group.