pith. machine review for the scientific record. sign in
theorem proved term proof

deriv_Jcost_one

show as:
view Lean formalization →

No prose has been written for this declaration yet. The Lean source and graph data below render without it.

generate prose now

formal statement (Lean)

 216theorem deriv_Jcost_one : deriv Jcost 1 = 0 := by

proof body

Term-mode proof.

 217  have h : HasDerivAt Jcost ((1 - 1⁻¹ ^ 2) / 2) 1 := hasDerivAt_Jcost 1 (by norm_num)
 218  simp at h
 219  exact h.deriv
 220
 221/-!
 222## Strict Convexity of Jcost
 223
 224The theorem `Jcost_strictConvexOn_pos : StrictConvexOn ℝ (Set.Ioi 0) Jcost`
 225is proven in `Cost/Convexity.lean` using the second derivative approach:
 226J''(x) = x⁻³ > 0 for x > 0.
 227
 228Import `IndisputableMonolith.Cost.Convexity` to access this theorem.
 229-/
 230

used by (1)

From the project-wide theorem graph. These declarations reference this one in their body.

depends on (13)

Lean names referenced from this declaration's body.