Randomised twisted Toeplitz spectral-measure conjecture

Less than 1 year old · traced to

Let a(x,z)a(x,z) be the symbol on [0,1]×T[0,1]\times\mathbb{T}

a(x,z)=∑j=−qpaj(x)zj,a(x,z)=\sum_{j=-q}^p a_j(x)z^j,

where aj(x)a_j(x) are continuous complex-valued functions on [0,1][0,1]. Let Tn(a)\mathcal{T}_n(a) be the randomised twisted Toeplitz matrix defined in the source, and let νx\nu_x be the weak limit of the eigenvalue-counting measures of the frozen Toeplitz matrices associated with ax=a(x,⋅)a_x=a(x,\cdot). Define

μn=1n∑λ∈sp⁡(Tn(a))δλ.\mu_n=\frac{1}{n}\sum_{\lambda\in\operatorname{sp}(\mathcal{T}_n(a))}\delta_\lambda.

Randomised twisted Toeplitz spectral-measure conjecture. The measures μn\mu_n converge weakly to

μ=∫01νx dx.\mu=\int_0^1\nu_x\,dx.

This conjecture predicts the same averaged frozen-symbol limit for random sampling points in the symbol as for structured banded perturbations. The supplied source does not state whether the conjecture has been resolved.

References

Primary source

Dario Giandinoto and Boris Shapiro, “Structured perturbations of tridiagonal twisted Toeplitz matrices”, arXiv:2604.20617 (2026).

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.