Section 12 pasting: half-sandwich move-back chain #
The reverse part of the finite commutation chain used in lem:commute-g-half-sandwich: after the
initial move chain and the flat post-move comparison, these families bring the leading
completed-slice measurement back to the position required by the rotated half-sandwich endpoint.
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").
The move-back family takes the symmetric model S : SymModel 𝔓 K as its first explicit argument,
as the placed families of Setup/Definitions and MoveChain/Lifting do:
commuteGHalfSandwich_moveBackChainFamily S params family r i. The lemmas take S second, after
params: commuteGHalfSandwich_commute_to_moveBackChainFamily_zero params S family zeta hsc where
the vendored ψbi was, and the three outcome identities, whose vendored versions have no state,
gain it there. No vendored lemma here has a swap, density or normalization hypothesis. The
swapped-front equivalences are classical and imported from the vendored MoveChain/Lifting.
The outcome identities hold by association and S.rightTensor_mul_rightTensor up to
definitional equality through the swapped-front equivalences, Fin.cons and pointTupleTail,
where the vendored proofs unfold by simp; at index 0 the move-back family is the second-slice
lift of the last move-chain family by definitional equality (r - 0 = r), so
commuteGHalfSandwich_moveChainFamily_last applies directly. The identity
commuteGHalfSandwich_moveBackChainFamily_zero_eq_secondSliceLift_moveFamily is declared before
commuteGHalfSandwich_commute_to_moveBackChainFamily_zero, the reverse of the vendored order, so
that the latter cites it rather than repeating its proof, as the vendored proof does.
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
Move-back chain #
Reverse the move-chain indexing so that the leading completed-slice factor is moved back through the product.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The second-slice lift of the r-move family is the move-step middle family, after exposing
the first tail coordinate and swapping the two distinguished slices.
The (r + 1)-move commuted endpoint is the move-step target family, after exposing the first
tail coordinate and swapping the two distinguished slices.
The first family of the move-back chain is the second-slice lift of the r-move family.
The commuted endpoint is close to the first family of the move-back chain, at the self-consistency error.