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Deterministic Frobenius normal form with transformation in O(n^ω) time

Establish a deterministic algorithm that, given an n×n matrix A over an effective field F, computes the Frobenius normal form of A together with an explicit transformation matrix P such that P^{-1} A P equals the Frobenius form, using O(n^ω) arithmetic operations in F, thereby matching the best-known Las Vegas probabilistic bound.

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Background

The paper notes that existing algorithms can compute the Frobenius normal form in O(nω) operations using Las Vegas probabilistic methods, but no deterministic algorithm achieving the same bound and producing a transformation matrix is currently known.

The authors present improved deterministic complexity bounds for related tasks but emphasize that achieving O(nω) deterministically for both the form and the transformation remains unresolved.

References

It is still an open question to obtain the same complexity bound with a deterministic algorithm, and also to compute an associated transformation matrix.

Computing Krylov iterates in the time of matrix multiplication (2402.07345 - Neiger et al., 12 Feb 2024) in Section 6.1 (Frobenius normal form)