The symmetric strategy of a two-space strategy #
Theorem D of reports/c6b-paper-proofs.md, ยง4 (Lemma 12; symmetrization placed after the bridge),
for the doubled model Doubling.model hM hฯ of Co/Doubling/Model.lean. A two-space projective
strategy strategy : ProjStrat params ๐ ๐ โฌ (Co/Test/StrategyCore.lean) whose state M is a
finite pair doubles to a symmetric strategy Doubling.symmStrat strategy hM of the doubled model,
whose every measurement family is the componentwise pairing of the first and the second player's,
and the failure probabilities of the doubled strategy are the role averages of the two-space
surrogate of Co/Test/StrategyBiProj/Measurements.lean:
symmStrat_axisParallel_eq_roleAverage:axis(S_D) = axisParallelRoleAverage(S);symmStrat_selfConsistency_eq_pointAgreement:selfCons(S_D) = pointAgreement(S);symmStrat_diagonal_eq_roleAverage:diag(S_D) = diagonalRoleAverage(S);symmStrat_isGood_three_mul: a strategy passing the test with errorฮตdoubles to a(3ฮต, 3ฮต, 3ฮต)-good symmetric strategy, the constants of the vendoredroleRegisterSymmStrategy_is_good_three_mul(LDT/Test/StrategyBiProjRoleAverage/Final.lean), which this replaces.
The pairing. SubMeas.prod, Measurement.prod and ProjMeas.prod pair two families with the
same outcomes into the product algebra, componentwise; Doubling.pairProjMeas hM P Q translates
the pairing of P in ๐ and Q in โฌ to the doubled local algebra Loc M along
Doubling.equiv (Co/Doubling/FinitePair.lean). Its components are P and Q again
(subMeasA_pairProjMeas, subMeasB_pairProjMeas). Covariance holds componentwise
(pairAxisParallel_reparamInvariant, pairDiagonal_reparamInvariant).
The halving (bipartiteConsError_model): the port's symmetric-model defect of two families of
the doubled model is the average of the two two-space defects of M at their components, the
max 0 of the definitions being inactive on both sides (qBipartiteConsDefect_model of
Co/Doubling/Halving.lean). So a doubled defect at most ฯ bounds each role assignment by 2ฯ
(bipartiteConsError_components_le_two_mul), the arithmetic of Theorem E (unsymmetrization at the
vendored cut), whose input, the point consistency of the ported mainInduction's measurement, is
milestone M13's. For measurements the two-space defect is the inconsistency of M
(bipartiteConsError_eq_inconsistency), the form MIPRE.LIDT.Simul.SoundIn concludes with.
Componentwise pairing #
The componentwise pairing (A โ B)_a = (A_a, B_a) of two submeasurements with the same
outcomes, a submeasurement of the product algebra.
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The componentwise pairing of two measurements, a measurement of the product algebra.
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The componentwise pairing of two projective measurements, a projective measurement of the product algebra.
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The outcomes of a paired projective measurement are the pairs of outcomes.
Postprocessing commutes with the image under a โ-homomorphism.
The two-space defect of measurements is the inconsistency #
The two-space consistency error of two measurement families is the inconsistency of M
(MIPRE.BipartiteModel.inconsistency), weighted by the question distribution: the form of the
consistency conclusions of MIPRE.LIDT.Simul.SoundIn.
The components of a submeasurement #
The first components of a submeasurement of the doubled local algebra, a submeasurement
of ๐ (the image under compA).
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The second components of a submeasurement of the doubled local algebra, a submeasurement
of โฌ (the image under compB).
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Taking first components commutes with postprocessing.
Taking second components commutes with postprocessing.
The halving of the bipartite defect #
The bipartite defect halves (Theorem C of reports/c6b-paper-proofs.md, ยง4), in the
vocabulary of the two-space defect: the symmetric-model defect of two submeasurements of the
doubled model is the average of the two-space defects of M at the components Xยน, Yยฒ and
Yยน, Xยฒ.
The averaged bipartite defect halves: the symmetric-model consistency error of two
families of the doubled model is the average of the two-space consistency errors of M at their
components.
Each role assignment costs at most twice the doubled defect (the arithmetic of Theorem E
of reports/c6b-paper-proofs.md, ยง4, Lemma 13): if the doubled defect of two families is at most
ฯ, each of the two two-space defects of M at their components is at most 2ฯ.
The paired measurements #
The paired projective measurement in the doubled model: the componentwise pairing of a
projective measurement P of ๐ and Q of โฌ, translated to the doubled local algebra
Loc M along Doubling.equiv.
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The outcomes of a paired projective measurement are the translated pairs of outcomes.
The first components of a paired projective measurement are the first measurement.
The second components of a paired projective measurement are the second measurement.
Covariance, componentwise #
Covariance of the paired axis-parallel measurements: if both players' axis-parallel families are covariant under rebasing, so is their pairing.
Covariance of the paired diagonal measurements: if both players' diagonal families are covariant under rebasing, so is their pairing.
The symmetric strategy #
The symmetric strategy of a two-space strategy (Theorem D of
reports/c6b-paper-proofs.md, ยง4): on the doubled model of the strategy's state, every family is
the componentwise pairing of the first and the second player's, and the line families are
covariant componentwise. This replaces the vendored role-register symmetrization
ProjStrat.roleRegisterSymmStrategy.
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- One or more equations did not get rendered due to their size.
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The state of the symmetric strategy is the doubled model.
The point measurements of the symmetric strategy are the paired point measurements.
The axis-parallel measurements of the symmetric strategy are the paired axis-parallel measurements.
The diagonal measurements of the symmetric strategy are the paired diagonal measurements.
The failure probabilities are the role averages #
The axis-parallel branch (Theorem D): the axis-parallel failure probability of the
symmetric strategy is the two-space role average axisParallelRoleAverage.
For a measurement (total 1), the bipartite strong self-consistency defect of a symmetric
model is its bipartite consistency defect with itself.
The self-consistency branch (Theorem D): the self-consistency failure probability of the
symmetric strategy is the two-space point agreement pointAgreementFailureProbability.
The diagonal branch (Theorem D): the diagonal failure probability of the symmetric
strategy is the two-space role average diagonalRoleAverage.
Symmetrization after the bridge (Theorem D of reports/c6b-paper-proofs.md, ยง4): a
two-space strategy on a finite pair passing the low-individual-degree test with error ฮต doubles
to a (3ฮต, 3ฮต, 3ฮต)-good symmetric strategy, the constants of the vendored
roleRegisterSymmStrategy_is_good_three_mul.