The dg-shifted Yangian structure theorem for perturbative 3d holomorphic-topological QFT

Let ${\mathcal A}$ be the algebra of local operators in a perturbative 3d holomorphic-topological QFT, and let ${\mathcal A}^!$ be its Koszul-dual $A_\infty$ algebra. A dg-shifted Yangian is the graded $A_\infty$ algebraic structure defined in the paper, including translations, a Maurer–Cartan element, a twisted coproduct, unit, counit, and the stated compatibility axioms. The dg-shifted Yangian structure theorem. In a perturbative 3d holomorphic-topological QFT, the $A_\infty$ algebra ${\mathcal A}^!$ that is Koszul-dual to local operators has the structure of a dg-shifted Yangian. The source explicitly labels this a physics theorem and motivates it by consistency of operator-product expansions, so it is recorded as solved rather than as an open conjecture.