For a finite dimensional unital complex simple Jordan superalgebra J, the Tits-Kantor-Koecher construction yields a 3-graded Lie superalgebra g ♭ ∼ = g ♭ (−1) ⊕ g ♭ (0) ⊕ g ♭ (1), such that g ♭ (−1) ∼ = J. Set V := g ♭ (−1) * and g := g ♭ (0). In most cases, the space P(V ) of superpolynomials on V is a completely reducible and multiplicity-free representation of g, and there exists a direct sum decomposition P(V ) := λ∈Ω V λ , where (V λ ) λ∈Ω is a family of irreducible g-modules parametrized by a set of partitions Ω. In these cases, one can define a natural basis (D λ ) λ∈Ω of "Capelli operators" for the algebra PD(V ) g of g-invariant superpolynomial differential operators on V . In this paper we complete the solution to the Capelli eigenvalue problem, which asks for the determination of the scalar cµ(λ) by which Dµ acts on V λ .We associate a restricted root system Σ to the symmetric pair (g, k) that corresponds to J, which is either a deformed root system of type A(m, n) or a root system of type Q(n). We prove a necessary and sufficient condition on the structure of Σ for P(V ) to be completely reducible and multiplicityfree. When Σ satisfies the latter condition we obtain an explicit formula for the eigenvalue cµ(λ), in terms of Sergeev-Veselov's shifted super Jack polynomials when Σ is of type A(m, n), and Okounkov-Ivanov's factorial Schur Q-polynomials when Σ is of type Q(n). Along the way, we prove that the natural map from the centre of the enveloping algebra of g into PD(V ) g is surjective in all cases except when J ∼ = F , where F is the 10-dimensional exceptional Jordan superalgebra. . Science Foundation (DMS-162350), the Fields Institute, and the University of Ottawa for funding this workshop. 1 We remark that g ♭ is a slight modification of the simple Lie superalgebra that is constructed from J by the Kantor functor (see Remark A.3).
(45)HC(j(z)) = res(HC(z)) for z ∈ Z(g).
Recall that by Pwe denote the standard degree filtration of the polynomial algebra P J defined in (9). Let τ J : a * Ω → C n J and τ * J : P J → P (a * Ω ) be defined as in (10) and (14), respectively. Since τ J is a bijection, τ * J is an isomorphism of C-algebras. If J ∼ = F , then by Proposition 4.2, for every µ ∈ Ω d there exists an element z µ ∈ Z (d) (g) such that res(HC(z µ )) = τ * J (P J,µ ) , where P J,µ is as in Definition 1.11. Theorem 1.13 follows from Proposition 5.2(iii).Proposition 5.2. Assume that J ∼ = F . Then the following assertions hold. (i) j (z µ ) = D µ for all µ ∈ Ω. (ii) j(Z(g)) = PD (V ) g . (iii) HC Dµ (λ) = P J,µ (τ J (λ)) for all λ, µ ∈ Ω.Proof. (i) By a direct computation, from Theorem 1.8 and Theorem 1.10 it follows that P J,µ τ J (µ) = d! and P J,µ (τ J (λ)) = 0 for all λ ∈ d k=0 Ω k \{µ}.