Section 12 pasting: half-sandwich flat-chain steps #
The adjacent-edge estimates for the post-move and combined flat chains, the local inputs to the
final chain composition in the proof of commuteGHalfSandwich_core: the counterpart of the
vendored file of the same path under MIPRE/Background/LIDT/MIPStarRE/LDT/ in the port of
planning/c6b-plan.md (milestone M11, section "Port conventions").
Both lemmas take the symmetric model S : SymModel 𝔓 K second, after params, where the vendored
ψbi was: commuteGHalfSandwich_postMoveFlatStep params S family gamma zeta hsc hcom r i and
commuteGHalfSandwich_flatChainStep params S family gamma zeta hsc hcom r i. Neither has a swap,
density or normalization hypothesis in the vendored file.
Where the vendored proofs compare outcomes by simp and transport each edge along
sddOpRel_congr_outcome, these rewrite the two families of the edge and its error to the
families of a step lemma, as equalities of families: the recursions unfold by ite_eq_left,
ite_eq_right, dite_eq_left and dite_eq_right, and an index whose value is not
definitionally that of the step lemma's index is moved by Fin.ext. Outcome identities remain at
the two edges whose families agree only outcome by outcome: the base edge of the post-move chain
(commuteGHalfSandwich_commuteFamily_zero_eq_recursiveTarget) and its edge into the move-back
chain (commuteGHalfSandwich_postMoveFlatFamily_zero_active,
commuteGHalfSandwich_moveBackChainFamily_zero_eq_secondSliceLift_moveFamily). The base edge of
the combined chain is the commutation step at r = 0, as the vendored
commuteGHalfSandwich_postMoveFlatStep at 0 is, with the move family and the move source
identified outcome by outcome.
Not ported #
Every declaration of the vendored file has a counterpart here.
References #
In LionSR/MIPStarRE at commit 507e8122, not in this repository:
references/ldt-paper/ld-pasting.texblueprint/src/chapter/ch09_pasting.tex
Flat-chain step lemmas #
postMoveFlatStep builds the edges within the post-move phase, and
flatChainStep stitches the move-chain prefix and the post-move suffix
into one combined chain.
Adjacent families of the post-move flat chain are at the error of the post-move error sequence.
Adjacent families of the combined flat chain are at the error of the combined error sequence.