Proposition 2.3 for Γ_R: |Sur(Γ_R, G)| = admissibleCountR G (Roe note Definition 1.1) #
The Roe-candidate twin of GQ2/Prop23.lean (paper Prop. 2.3 ⟦prop-epi-semantics⟧, §2.2): for
every finite discrete group G, continuous surjections Γ_R ↠ G correspond bijectively to
R-admissible marked generating quadruples in G (note Definition 1.1 ⟦def:GammaR⟧), so
prop_2_3_R : Nat.card (ContSurj GammaR G) = admissibleCountR G.
This is the Γ_R half of the surjection-count semantics; prop_2_3_R is stated in exactly the
shape the Roe main-presentation schematic (ticket R32) consumes, mirroring how prop_2_3 feeds
main_presentation (GQ2/Statement.lean, via GQ2/PresentationLiteral.lean).
What is cloned and what is reused #
Only the parts where the Roe wild relation actually enters are re-derived with an R-suffix;
the word-independent round-trip scaffolding is imported and reused verbatim:
- reused (word-independent, from
GQ2/GammaA.leanandGQ2/Prop23.lean):univMarking,Marking.toHom,univMarking_map_toHom,Marking.toHom_hom_univMarking_map,quotientMk,quotientLift,surjective_of_map_generates, and — crucially —Marking.classifyitself (the classified hom of a marking istoHom-only, no relator enters); - cloned (the Roe wild relation enters through
AdmissibleR/N_R):admissibleR_of_NR_le_ker(converse of R3'sNR_le_ker, proved from R3'sisAdmissibleUR_of_NR_le+Marking.map_admissibleR),Marking.pushR,Marking.pushR_admissible,Marking.classifyR_ker(viaNR_le_ker),Marking.descendRand its round trips,contSurjEquivAdmissibleR, andprop_2_3_R.
§5-duality supply input #
The section markC_R / markC_admissible_R (the Roe twin of GQ2.WordCohBridge.markC /
markC_admissible, GQ2/WordCohBridge.lean) is colocated here for convenience — it is not a
prop_2_3_R dependency, but the input the §5 word-cohomology self-duality (prop_5_15_R, tickets
R26/R31) consumes at markC_R θ, in the same adm.1 / adm.2.1 / adm.2.2.1 / adm.2.2.2 projection
shape (Generates / TameRel / WildRelR / Pro2Core) as GQ2/MStageCountGammaA.lean.
Everything is at the standard three axioms (Ax = ∅).
The universal property, uniqueness half — REUSED #
Marking.toHom_hom_univMarking_map (GQ2/Prop23.lean) is word-independent (it mentions only
univMarking/Marking.toHom), so it is imported and reused; no R-suffix twin is needed.
The converse of NR_le_ker #
Converse of R3's NR_le_ker (Roe twin of GQ2.admissible_of_NA_le_ker): if a continuous
homomorphism f : F₄ → G into a finite discrete group is surjective and kills N_R, then the
pushed universal marking of G is R-admissible. Proof cloned verbatim from the Γ_A case,
swapping isAdmissibleU_of_NA_le → isAdmissibleUR_of_NR_le, IsAdmissibleU → IsAdmissibleUR and
Marking.map_admissible → Marking.map_admissibleR: ker f is then an open normal subgroup above
N_R, hence R-admissible (isAdmissibleUR_of_NR_le, GQ2/Roe/AdmissibleLimit.lean), and
R-admissibility transfers to G along F₄ ⧸ ker f ≃* G (Marking.map_admissibleR,
GQ2/Roe/GammaR.lean). Together with NR_le_ker this is the note's "quotients of Γ_R = the
R-admissible quotients".
The two directions of the bijection, as named constructions #
The marking of G pushed forward from the universal marking along φ : F₄ ⧸ N_R → G. Roe
twin of GQ2.Marking.push.
Equations
- GQ2.Marking.pushR φ = GQ2.Marking.map (φ.comp (GQ2.quotientMk GQ2.NR)).toMonoidHom GQ2.univMarking
Instances For
The pushed marking of a continuous surjection is R-admissible (forward direction of
prop_2_3_R). Roe twin of GQ2.Marking.push_admissible.
The descended hom Γ_R → G of an R-admissible marking (backward direction of prop_2_3_R).
Roe twin of GQ2.Marking.descend.
Equations
- t.descendR ht = GQ2.quotientLift GQ2.NR t.classify ⋯
Instances For
Pushing the descended hom recovers the marking (round-trip 1). Roe twin of
GQ2.Marking.push_descend.
Descending the pushed marking recovers the surjection (round-trip 2, via the uniqueness half of
the universal property Marking.toHom_hom_univMarking_map). Roe twin of
GQ2.Marking.descend_push.
Prop 2.3 for Γ_R #
Prop. 2.3 for Γ_R, bijection form (paper §2.2 ⟦prop-epi-semantics⟧ / note Definition 1.1
⟦def:GammaR⟧): continuous surjections Γ_R ↠ G correspond to R-admissible markings of G.
(Stated on the underlying quotient F₄ ⧸ N_R, to which GammaR is definitionally equal.)
Equations
- One or more equations did not get rendered due to their size.
Instances For
Proposition 2.3 for Γ_R (paper §2.2 ⟦prop-epi-semantics⟧ / note Definition 1.1
⟦def:GammaR⟧): the number of continuous surjections Γ_R ↠ G onto a finite discrete group equals
admissibleCountR G, the number of R-admissible marked generating quadruples in G. Stated in
exactly the hΓR shape the Roe main_presentation schematic (ticket R32) consumes, mirroring how
prop_2_3 feeds main_presentation.
§5-duality supply: markC_R and markC_admissible_R #
Not a prop_2_3_R dependency — colocated for the §5 word-cohomology self-duality (prop_5_15_R,
tickets R26/R31). markC_R is the Roe twin of GQ2.WordCohBridge.markC (there markC q = Marking.push q), and markC_admissible_R wraps Marking.pushR_admissible, matching the
adm.1 / adm.2.1 / adm.2.2.1 / adm.2.2.2 projection shape (Generates / TameRel / WildRelR / Pro2Core) that GQ2/MStageCountGammaA.lean feeds to prop_5_15.
The pushed marking t_q : Marking C of a continuous surjection q : Γ_R ↠ C — the Roe twin of
GQ2.WordCohBridge.markC, against which the §5 word complex is formed.
Equations
- GQ2.markC_R q = GQ2.Marking.pushR q
Instances For
The pushed marking of a continuous surjection q : Γ_R ↠ C is R-admissible — the §5-duality
supply input (prop_5_15_R, tickets R26/R31), Roe twin of GQ2.WordCohBridge.markC_admissible.
Stress test (consumption shape). The four projections of markC_admissible_R land in the
Roe clauses Generates / TameRel / WildRelR / Pro2Core, in the adm.1 / adm.2.1 / adm.2.2.1 / adm.2.2.2 order that GQ2/MStageCountGammaA.lean feeds to prop_5_15 — so prop_5_15_R's callers
(R26/R31) reuse markC_admissible_R θ hθs verbatim. Pins the Roe wild relation WildRelR (not the
Γ_A WildRel) at the .2.2.1 slot.
Paper-tag ledger (paper §2.2 + Roe note paper/roe-presentation-verification.tex; #
hand-maintained)
- Proposition 2.3 = ⟦prop-epi-semantics⟧ (the epi-semantics cloned for
Γ_R) - Definition 1.1 = ⟦def:GammaR⟧