Manuscript XIV-E@1 · XIV-E.tex · theorem · e89fd2a5
Theorem: Exact regrouping of the complete retained expression
E1: exact calculation of the complete precomposition sum › The first calculation: the entire six-branch sum · lines 661–717 · proof included or linked
XIV-E@1#thm:regroup, XIV-E@1#eq:fullregroup
For all smooth directions for which the inherited slab response formulas are used,
This identity retains all six branches. It involves no characteristic composition and no regularization.
Proof. Symmetry of gives
Compact integration by parts in the second term of yields
The last integral cancels exactly. The first term of and the remaining integral are precisely
Next, the definition of expresses as the retarded inverse of the divergence of the first two terms in (eq:Btensor). The third term is . Since
the fourth term gives , with its inherited sign. Linearity of combines these three branches.
Finally is unchanged. Adding the three groups proves (eq:fullregroup).
Displayed formulas in this passage
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