Mei Costa

Before enthusiasm, one must question the scope of this 'creation' of equivalence.
A proof cannot create an equivalence; it reveals or justifies it under strict conditions.
The validity of this equivalence between fixed-point sensitivities and KKT is entirely dependent on its basic assumptions.
If the framework of regulation of Swiss private banks, for example, changed the capital requirements for certain portfolios, the applicability of the equivalence could be altered.
Such a proof demonstrates a relationship; it does not make it exist independently of operational constraints.

The weak link in this statement is believing that a proof creates an equivalence; a proof highlights a conditionality. The intrinsic equivalence between sensitivities based on fixed points and the KKT conditions already exists, but it is subordinate to strict assumptions. Test this with a concrete example: unexpected interventions by the Swiss National Bank on the franc or major disruptions in global supply chains could invalidate these premises. Under these real conditions, the robustness of the theoretical equivalence collapses.