Explanation of symmetry_inv
(1) In plain English, the declaration asserts that if a map T on a nonempty type X is bijective and J is invariant under T (J(T x) equals J x for every x), then J is also invariant under the inverse map of T.
(2) In Recognition Science this matters because the cost functional J must support a group-like structure of symmetries for the ledger to remain balanced under reversible transformations; the result ensures the set of J-preserving maps is closed under inversion, a prerequisite for deriving conserved quantities from cost stationarity.
(3) The formal statement is read as: for any nonempty type X, any function T : X → X, and any J : X → ℝ, if T is bijective and IsSymmetryOf T J holds, then IsSymmetryOf (Function.invFun T) J holds. The proof proceeds by substituting the right-inverse property of invFun into the invariance assumption for T.
(4) Visible dependencies in the supplied source are the definition IsSymmetryOf (used directly in the hypothesis and conclusion) together with the surrounding theorems id_is_symmetry and symmetry_comp that establish basic closure properties of symmetries. The module imports Mathlib and IndisputableMonolith.Cost but introduces no axioms or sorrys for this declaration.
(5) The declaration does not prove that the inverse map is itself bijective (though this follows from the hypothesis), does not establish conservation of any quantity along a flow, and does not instantiate the result to the concrete J-cost or physical symmetries appearing elsewhere in the Recognition Science framework.