A bound for the Waring rank of the determinant via syzygies

An improved upper bound for the Waring rank of the determinant

The Waring rank of the generic $d \times d$ determinant is bounded above by $d \cdot d!$. This improves previous upper bounds, which were of the form an exponential times the factorial. Our upper bound comes from an explicit power sum decomposition. We describe some of the symmetries of the decomposition and set-theoretic defining equations for the terms of the decomposition.

Syzygies of the apolar ideals of the determinant and permanent

We investigate the space of syzygies of the apolar ideals $\det_n^\perp$ and ${\rm perm}_n^\perp$ of the determinant $\det_n$ and permanent ${\rm perm}_n$ polynomials. Shafiei had proved that these ideals are generated by quadrics and provided a minimal generating set. Extending on her work, in characteristic distinct from two, we prove that the space of relations of $\det_n^{\perp}$ is generated by linear relations and we describe a minimal generating set. The linear relations of ${\rm perm}_n^{\perp}$ do not generate all relations, but we provide a minimal generating set of linear and quadra…

Lower bound for ranks of invariant forms

We give a lower bound for the Waring rank and cactus rank of forms that are invariant under an action of a connected algebraic group. We use this to improve the Ranestad--Schreyer--Shafiei lower bounds for the Waring ranks and cactus ranks of determinants of generic matrices, Pfaffians of generic skew-symmetric matrices, and determinants of generic symmetric matrices.

High rank linear syzygies on low rank quadrics

We study the linear syzygies of a homogeneous ideal I in a polynomial ring S, focusing on the graded betti numbers b_(i,i+1) = dim_k Tor_i(S/I, k)_(i+1). For a variety X and divisor D with S = Sym(H^0(D)*), what conditions on D ensure that b_(i,i+1) is nonzero? Eisenbud has shown that a decomposition D = A + B such that A and B have at least two sections gives rise to determinantal equations (and corresponding syzygies) in I_X; and conjectured that if I_2 is generated by quadrics of rank at most 4, then the last nonvanishing b_(i,i+1) is a consequence of such equations. We describe obstruction…

Waring秩的固定参数去边界化

Fixed-parameter debordering of Waring rank

本研究首次获得多项式Waring秩的上界，该上界关于边界Waring秩指数增长、关于次数线性增长，解决了去边界化问题，并改进了常数边界Waring秩情形下的结果。

$x_1\cdots x_n$ 的边界 Waring 秩为 $2^{n-1}$

The border Waring rank of $x_1\cdots x_n$ is $2^{n-1}$

本文证明特征零域上单项式 $x_1\cdots x_n$ 的边界 Waring 秩为 $2^{n-1}$，表明极化恒等式为最优分解，下界证明借助非对称的行列式张量的高阶 Koszul 展平。