Linear-time inverse positive definite Hankel factorization conjecture

About 3 years old · traced to

Let H∈Rn×n\mathbf{H} \in \mathbb{R}^{n\times n} be a positive definite Hankel matrix with bit complexity ℓ\ell and condition number bounded by 2ℓ2^\ell. An inverse symmetric positive factorization algorithm should find a representation of a matrix B\mathbf{B} with nn rows, O~(n)\tilde{O}(n) columns, and bit complexity ℓ\ell in time O~(nω/2⋅ℓ)\tilde{O}(n^{\omega/2} \cdot \ell) such that

∥H−1−BB∗∥F⁡<12ℓ.\left\|\mathbf{H}^{-1}-\mathbf{B}\mathbf{B}^*\right\|_{\operatorname{F}}<\frac{1}{2^{\ell}}.

This conjecture would provide a positive-semidefinite symmetric factorization for the inverse of a positive definite Hankel matrix within the stated subquadratic running time. It complements the paper's difference-of-positive-factorizations approach for Hankel matrices and their inverses; the supplied text gives no resolution of this conjecture.

References

Primary source

Mehrdad Ghadiri, “On Symmetric Factorizations of Hankel Matrices”, arXiv:2307.00805 (2023).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.