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Books.ConvexAnalysis_Rockafellar_1970.Chap06.section30_part7

Helper for Theorem 6.30.11: once a closed convex bifunction fails properness, its graph function is an improper convex function on univ.

theorem helperForTheorem_6_30_11_concaveBifunctionClosure_eq_self_of_eq_const_top {m n : } {G : (Fin m)(Fin n)EReal} (hTop : G = fun (x : Fin m) (x_1 : Fin n) => ) :

Helper for Theorem 6.30.11: the concave bifunction closure fixes the constant bifunction.

theorem helperForTheorem_6_30_11_concaveBifunctionClosure_eq_self_of_eq_const_bot {m n : } {G : (Fin m)(Fin n)EReal} (hBot : G = fun (x : Fin m) (x_1 : Fin n) => ) :

Helper for Theorem 6.30.11: the concave bifunction closure fixes the constant bifunction.

Helper for Theorem 6.30.11: once a closed concave bifunction fails properness, the negated graph function is an improper convex function on univ.

Helper for Theorem 6.30.11: a closed improper convex bifunction graph can only take the values and .

Helper for Theorem 6.30.11: once a closed concave bifunction is improper, its negated graph also takes only the values and .

theorem helperForTheorem_6_30_11_improper_convex_fixed_point_eq_const_top_or_bot {m n : } {F : (Fin m)(Fin n)EReal} (hImproper : ImproperConvexFunctionOn Set.univ (bifunctionGraphFunction F)) (hFixed : convexBifunctionClosure F = F) :
(F = fun (x : Fin m) (x_1 : Fin n) => ) F = fun (x : Fin m) (x_1 : Fin n) =>

Helper for Theorem 6.30.11: if an improper convex bifunction graph is fixed by the current Chapter 2 closure, then the bifunction must already be constant or constant .

theorem helperForTheorem_6_30_11_improper_concave_fixed_point_eq_const_top_or_bot {m n : } {G : (Fin m)(Fin n)EReal} (hImproper : ImproperConvexFunctionOn Set.univ fun (z : Fin (m + n)) => -bifunctionGraphFunction G z) (hFixed : concaveBifunctionClosure G = G) :
(G = fun (x : Fin m) (x_1 : Fin n) => ) G = fun (x : Fin m) (x_1 : Fin n) =>

Helper for Theorem 6.30.11: if the negated graph of an improper concave bifunction is fixed by the current Chapter 2 closure, then the bifunction must already be constant or constant .

theorem helperForTheorem_6_30_11_convexBifunctionClosure_ne_self_of_closed_not_proper_nonconstant {m n : } {F : (Fin m)(Fin n)EReal} (hClosed : ClosedConvexBifunction F) (hNotProper : ¬ProperConvexBifunction F) (hNotTop : F fun (x : Fin m) (x_1 : Fin n) => ) (hNotBot : F fun (x : Fin m) (x_1 : Fin n) => ) :

Helper for Theorem 6.30.11: in the closed improper nonconstant convex branch, the current Chapter 2 closure semantics force the failure of the desired fixed-point identity.

theorem helperForTheorem_6_30_11_concaveBifunctionClosure_ne_self_of_closed_not_proper_nonconstant {m n : } {G : (Fin m)(Fin n)EReal} (hClosed : ClosedConcaveBifunction G) (hNotProper : ¬ProperConcaveBifunction G) (hNotTop : G fun (x : Fin m) (x_1 : Fin n) => ) (hNotBot : G fun (x : Fin m) (x_1 : Fin n) => ) :

Helper for Theorem 6.30.11: in the closed improper nonconstant concave branch, the current Chapter 2 closure semantics force the failure of the desired fixed-point identity after negating the graph.

theorem helperForTheorem_6_30_11_convexBifunctionClosure_eq_self_of_closed {m n : } {F : (Fin m)(Fin n)EReal} (hClosed : ClosedConvexBifunction F) (hGraphNeBot : ∀ (z : Fin (m + n)), bifunctionGraphFunction F z ) :

Helper for Theorem 6.30.11: a closed convex bifunction whose graph never attains is fixed by the canonical graph closure. This is the graph-level lift of the Chapter 2 fixed-point theorem in the non- branch supported by the current closure API.

theorem helperForTheorem_6_30_11_concaveBifunctionClosure_eq_self_of_closed {m n : } {G : (Fin m)(Fin n)EReal} (hClosed : ClosedConcaveBifunction G) (hNegGraphNeBot : ∀ (z : Fin (m + n)), -bifunctionGraphFunction G z ) :

Helper for Theorem 6.30.11: a closed concave bifunction whose negated graph never attains is fixed by the canonical concave graph closure. This is the concave counterpart of the supported non- convex fixed-point theorem after negating the graph.

Helper for Theorem 6.30.11: in the convex branch, once the closure identity cl F = F is supplied, the biconjugation formula immediately collapses to the fixed-point statement F^{**} = F.

Helper for Theorem 6.30.11: in the concave branch, the fixed-point clause follows by rewriting the biadjoint as the canonical concave closure and then using cl F = F.

Theorem 6.30.11: for a convex or concave bifunction F : ℝ^m → ℝ^n, its adjoint is a closed bifunction of the opposite type from ℝ^n to ℝ^m, it is proper exactly when F is proper, and the biadjoint agrees with the appropriate closure of F. The textbook closed-case conclusion is formalized here through the explicit fixed-point identity cl F = F, i.e. through the closure operator appearing in the preceding biconjugation statement itself. Closed proper convex and closed proper concave bifunctions still correspond through adjunction, and polyhedrality is preserved by adjoints.