The mixed Heisenberg pairing as a Roe relator obstruction (mixedB_R = relZPairR) #
The Γ_R twin of GQ2/MixedBObs.lean. The Heisenberg 2-cocycle kappaHeis, the structural
isomorphism PhiHeis : CentExt kappaHeis →* HeisLift A C, and the base marking mBaseMarking
are word-independent and reused verbatim from the Γ_A file; only the two statements that
read a relator off a marking are re-derived at Marking.wildValueR:
mixedB_eq_relZPairR— the traced Heisenberg central coordinate of the Roe wild relator,mixedB_R t x y(GQ2/Roe/FoxBasic.lean), is the traced fibre coordinaterelZPairRofkappaHeis's lifted base marking. Same proof as theΓ_Aoriginal, withMarking.map_wildValueswapped forMarking.map_wildValueR.obs_inflation_R— theWordCoh2Robstruction of a continuous 2-cocycle onΓ_Rthat factors pointwise through a finite groupLis the Roe relator-zpair of the pushforward markinggammaGenR.map H. Stated atF₄ ⧸ N_R(not at the Demushkin quotientDR, whereGQ2/Roe/DRWordCoh.lean'sobs_DRlives), exactly asΓ_AbuildsobsatF₄ ⧸ N_A.
Together these are the source-generic, edge-free half of the Γ_R ledger identity
obs_R(varCoc u) = mixedB_R t_ρ x_w y_φ; the edge-specific half is assembled in
GQ2/LedgerGammaR.lean.
mixedB_R is a Roe relator-z pair. The traced Heisenberg central coordinate of the
Roe wild relator equals the traced fibre coordinate of kappaHeis's lifted base marking — i.e.
mixedB_R is a WordCoh2R relator obstruction. Γ_R twin of
MixedBObs.mixedB_eq_relZPair.
Obstruction of an inflated cocycle #
The WordCoh2R obstruction obs_R of a continuous 2-cocycle on Γ_R that factors pointwise
through a finite group L (φ(a,b) = κ(H a)(H b)) is the Roe relator-z pair of the pushforward
marking gammaGenR.map H. This packages the entire LevelFactorR / relZPairR_comap computation
once and generically, so the edge-specific ledger identity is a one-line application.
Obstruction of an inflated cocycle. If a continuous 2-cocycle φ on Γ_R factors
pointwise through a finite group L as φ(a,b) = κ(H a)(H b) for a continuous hom
H : Γ_R → L and a 2-cocycle κ on L, its Roe obstruction is the Roe relator-z pair of the
pushforward marking gammaGenR.map H. Γ_R twin of MixedBObs.obs_inflation, at F₄ ⧸ N_R.