Documentation

MIPRE.Background.LIDT.Co.Pasting.ComparisonLemmas.CommuteGHalfSandwich.MoveChain.BackChain

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:

Move-back chain #

Reverse the move-chain indexing so that the leading completed-slice factor is moved back through the product.

Equations
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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.