The theta-coordinate branch of Theorem 4.13 #
Each non-endpoint coordinate family from the all-submodularity classification is rigid, so the general genus-two nonrecurrence criterion applies without any residual graph-theoretic hypothesis.
theorem
Bananas.theta_distinctInterior_kGeneral_iff_nonRecurrent
{k : ℕ}
(B : Banana 2)
(alpha beta : Fin 3)
(i : Utilities.Certificate.SubdivisionGraph.Spec.PathPosition B alpha)
(j : Utilities.Certificate.SubdivisionGraph.Spec.PathPosition B beta)
(hi : Utilities.Certificate.SubdivisionGraph.Spec.IsInteriorPosition B alpha i)
(hj : Utilities.Certificate.SubdivisionGraph.Spec.IsInteriorPosition B beta j)
(hab : alpha ≠ beta)
(hTO :
IsTorsionOrder
(mark (Utilities.Certificate.SubdivisionGraph.Spec.graph B) (strandVertex B alpha i) (strandVertex B beta j)) k)
:
KGeneralTransmission
(mark (Utilities.Certificate.SubdivisionGraph.Spec.graph B) (strandVertex B alpha i) (strandVertex B beta j)) k ↔ NonRecurrent
(mark (Utilities.Certificate.SubdivisionGraph.Spec.graph B) (strandVertex B alpha i) (strandVertex B beta j)) k
Distinct interior theta strands: exact torsion plus nonrecurrence is equivalent to general transmission.
theorem
Bananas.theta_zeroPenultimate_kGeneral_iff_nonRecurrent
{k : ℕ}
(B : Banana 2)
(alpha : Fin 3)
(hlen : 2 ≤ B.length alpha)
(hTO :
IsTorsionOrder
(mark (Utilities.Certificate.SubdivisionGraph.Spec.graph B) (strandVertex B alpha ⟨0, ⋯⟩)
(strandVertex B alpha ⟨B.length alpha - 1, ⋯⟩))
k)
:
KGeneralTransmission
(mark (Utilities.Certificate.SubdivisionGraph.Spec.graph B) (strandVertex B alpha ⟨0, ⋯⟩)
(strandVertex B alpha ⟨B.length alpha - 1, ⋯⟩))
k ↔ NonRecurrent
(mark (Utilities.Certificate.SubdivisionGraph.Spec.graph B) (strandVertex B alpha ⟨0, ⋯⟩)
(strandVertex B alpha ⟨B.length alpha - 1, ⋯⟩))
k
The normalized (0,n-1) theta boundary family is rigid and hence obeys
the same exact nonrecurrence criterion.
theorem
Bananas.theta_oneLength_kGeneral_iff_nonRecurrent
{k : ℕ}
(B : Banana 2)
(alpha : Fin 3)
(hlen : 2 ≤ B.length alpha)
(hTO :
IsTorsionOrder
(mark (Utilities.Certificate.SubdivisionGraph.Spec.graph B) (strandVertex B alpha ⟨1, ⋯⟩)
(strandVertex B alpha ⟨B.length alpha, ⋯⟩))
k)
:
KGeneralTransmission
(mark (Utilities.Certificate.SubdivisionGraph.Spec.graph B) (strandVertex B alpha ⟨1, ⋯⟩)
(strandVertex B alpha ⟨B.length alpha, ⋯⟩))
k ↔ NonRecurrent
(mark (Utilities.Certificate.SubdivisionGraph.Spec.graph B) (strandVertex B alpha ⟨1, ⋯⟩)
(strandVertex B alpha ⟨B.length alpha, ⋯⟩))
k
The normalized (1,n) theta boundary family is rigid and hence obeys
the same exact nonrecurrence criterion.