Manuscript X-C-ST@1 · X-C-ST.tex · proposition · b679954e

Proposition: Three-term variation

Three-term variation and the completed identity › Proof of record · lines 1541–1623 · proof included or linked

X-C-ST@1#prop:variation, X-C-ST@1#eq:variation, X-C-ST@1#eq:var1, X-C-ST@1#eq:var2

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For arbitrary smooth classical backgrounds and arbitrary compact interior generators,

The first term is coefficientwise in . The other two are the dressed coordinate and switch defects.

Writing

the coefficient formulae are

Proof. Let . By Lemma lem:advanced,

The defect definitions give

Subtracting,

The right-hand side is a compact formal source: has support in , and the coefficients of have compact generator support.

The difference is advanced-type. Indeed, are advanced-type, and each coefficient of has compact generator support. No assumption that an unexpanded diffeomorphism preserves the completion causal relation is needed.

Advanced uniqueness therefore yields

Subtract and apply . Using proves (eq:variation).

Every coefficient of is a smooth compact function, so its -image lies in . Finally expand

The degree-one and degree-two coefficients are exactly (eq:var1) and (eq:var2).

Displayed formulas in this passage

  • X-C-ST@1#eq:variation · line 1545

  • X-C-ST@1#eq:var1 · line 1564

  • X-C-ST@1#eq:var2 · line 1564

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