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doc: Edits to Wick theorem docs

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jstoobysmith 2025-02-10 10:21:57 +00:00
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HepLean/PerturbationTheory/FieldStatistics/ExchangeSign.lean
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@ -27,8 +27,8 @@ variable {𝓕 : Type}
/-- The exchange sign, `exchangeSign`, is defined as the group homomorphism
`FieldStatistic →* FieldStatistic →* ℂ`,
for which `exchangeSign a b` is `-1` if both `a` and `b` are `fermionic` and `1` otherwise.
The exchange sign is sign one picks up on exchanging an operator or field `φ₁` of statistic `a`
with one `φ₂` of statistic `b`, i.e. `φ₁φ₂ → φ₂φ₁`.
The exchange sign is the sign one picks up on exchanging an operator or field `φ₁` of statistic
`a` with an operator or field `φ₂` of statistic `b`, i.e. `φ₁φ₂ → φ₂φ₁`.
The notation `𝓢(a, b)` is used for the exchange sign of `a` and `b`. -/
def exchangeSign : FieldStatistic →* FieldStatistic →* ℂ where