theorem
proved
term proof
J_composition_decomposition
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formal statement (Lean)
162theorem J_composition_decomposition (a b : ℝ) (ha : 0 < a) (hb : 0 < b) :
163 J (a * b) + J (a / b) = 2 * J a * J b + 2 * J a + 2 * J b := by
proof body
Term-mode proof.
164 unfold J Cost.Jcost
165 have ha0 : a ≠ 0 := ha.ne'
166 have hb0 : b ≠ 0 := hb.ne'
167 field_simp [ha0, hb0]
168 ring
169
170/-- Additive regime for independent events.
171
172When the interaction term vanishes (`J a * J b = 0`), the pairwise
173composition law reduces to pure additivity (up to the canonical factor 2). -/