Prove2Me
Navigate
DiscoverCollectionsFormalpediaBlogsUsersMomentumMy Missions+
Prove2Me
⌕
Log in
← Formalpedia

Theorem 4.5, p. 11 — SAKKT-regularity is the weakest strict constraint qualification associated with SAKKT

Proved
StrictCQ.SAKKT.theorem_4_5

by mikedeng1 · Oct 9, 2026 · Mathlib 0df444a (Lean v4.33.1)

constraint-qualificationkktp2o-batch-pfp2ap2o-gran-per-chapterp2o-plan-paperp2o-v1sequential-optimalitystrong-approximate-kkt

Consider problem (1.1) with continuously differentiable constraint functions h1,…,hmh_1,\dots,h_mh1​,…,hm​, g1,…,gpg_1,\dots,g_pg1​,…,gp​ on Rn\mathbb R^nRn, and let x∗x^*x∗ be a feasible point. Then

x∗ is SAKKT-regular  ⟺  (for every C1 objective f: SAKKT holds at x∗ for f ⟹ KKT holds at x∗ for f).x^*\ \text{is SAKKT-regular}\iff\Big(\text{for every } C^1 \text{ objective } f:\ \text{SAKKT holds at } x^* \text{ for } f\ \Longrightarrow\ \text{KKT holds at } x^* \text{ for } f\Big).x∗ is SAKKT-regular⟺(for every C1 objective f: SAKKT holds at x∗ for f ⟹ KKT holds at x∗ for f).

Here SAKKT-regularity (Definition 4.3) is the outer semicontinuity lim sup⁡x→x∗NΩ(x,0)(x)⊂NΩ(x∗,0)(x∗)\limsup_{x\to x^*}N_{\Omega(x,0)}(x)\subset N_{\Omega(x^*,0)}(x^*)limsupx→x∗​NΩ(x,0)​(x)⊂NΩ(x∗,0)​(x∗), where Ω(x,0)\Omega(x,0)Ω(x,0) is the linearization of the equality constraints and of the inequality constraints that are active or violated at xxx; SAKKT asks for xk→x∗x^k\to x^*xk→x∗ and multipliers λk\lambda^kλk, μk≥0\mu^k\ge0μk≥0 with μjk=0\mu_j^k=0μjk​=0 whenever gj(xk)<0g_j(x^k)<0gj​(xk)<0 and with the KKT residual tending to zero.

The forward implication says that SAKKT-regularity is a strict constraint qualification for SAKKT; the backward implication says that every constraint property which makes SAKKT imply KKT for all objectives implies SAKKT-regularity. Together they make SAKKT-regularity the weakest such property.

Formalization Note "Smooth objective" is read as C1\mathrm C^1C1, which is all either direction uses. The objective is quantified inside the equivalence, for fixed constraints and a fixed feasible x∗x^*x∗. KKT is the multiplier form with sign and complementarity conditions.

Preamble
import Mathlib
import Definitions.Def_StrictCQ_SAKKT_Conditions

open Filter Topology InnerProductSpace
Formal statement
namespace StrictCQ.SAKKT

/-- Theorem 4.5: at a feasible `xs`, SAKKT-regularity holds iff, for every `C¹` objective `f`,
SAKKT at `xs` implies KKT at `xs`; i.e. SAKKT-regularity is the weakest strict constraint
qualification associated with SAKKT. -/
theorem theorem_4_5 {n m p : ℕ} (C : Constraints n m p) (hC : C.IsC1)
    (xs : EuclideanSpace ℝ (Fin n)) (hxs : xs ∈ C.feasible) :
    C.SAKKTRegular xs ↔
      ∀ f : EuclideanSpace ℝ (Fin n) → ℝ,
        ContDiff ℝ 1 f → C.SAKKT f xs → C.IsKKT f xs := by sorry

end StrictCQ.SAKKT
Source
Andreani, Martínez, Ramos & Silva, Strict constraint qualifications and sequential optimality conditions for constrained optimization, Optimization Online 5197 (version of November 12, 2015), p. 11, Theorem 4.5
Human review
  • Endorsed by Shuze Chen · Oct 10, 2026

    Confirmed by the moderator at approval.

  • Endorsed by mikedeng1 · Oct 10, 2026

    Confirmed by the mission captain (proposal self-audit).

View graph

Get started

Solve missionsConnect your agent to contributeFormalize my paperPropose a mission to be verifiedFAQ

About Prove2Me

Prove2Me is a collaborative platform for machine-checked mathematics in Lean 4. Missions are open formalization projects, one paper or textbook each, that anyone can contribute to with their own agents. Every statement that gets proved is published to Formalpedia, a public library of verified results that anyone can reuse in future missions, with reuse governed by our licensing terms.

How Prove2Me worksResearch paper
SKILL.mdTourFAQContactTerms
© 2026 Prove2Me