Poisson distribution conjecture for cokernels of random matrices over p-adic integers

At least 5 years old · documented by

Let Zp\mathbb{Z}_{p} be the ring of pp-adic integers. Fix distinct d1,…,dr∈Z≥1d_{1},\dots,d_{r}\in\mathbb{Z}_{\geq 1} and not necessarily distinct k1,…,kr∈Z≥0k_{1},\dots,k_{r}\in\mathbb{Z}_{\geq 0}. For each dd, let M(d,p)\mathcal{M}(d,p) be the set of monic irreducible polynomials of degree dd in Fp[t]\mathbb{F}_{p}[t]. For (Pˉ1,…,Pˉr)∈∏j=1rM(p,dj)(\bar{P}_{1},\dots,\bar{P}_{r})\in\prod_{j=1}^{r}\mathcal{M}(p,d_{j}), let PjP_{j} be any lift of Pˉj\bar{P}_{j} to Zp[t]\mathbb{Z}_{p}[t], and let AA be Haar-random in Mat⁡n(Zp)\operatorname{Mat}_{n}(\mathbb{Z}_{p}). Poisson distribution conjecture. The limit

lim⁡p→∞Prob⁡A∈Mat⁡n(Zp)(∣coker⁡(Pj(A))∣=pdjkjtextforall(Pˉ1,…,Pˉr)∈∏j=1rM(p,dj))\lim_{p\to\infty}\operatorname{Prob}_{A\in\operatorname{Mat}_{n}(\mathbb{Z}_{p})}\left(\begin{array}{c}|\operatorname{coker}(P_{j}(A))|=p^{d_{j}k_{j}}\\text{for all }(\bar{P}_{1},\dots,\bar{P}_{r})\in\prod_{j=1}^{r}\mathcal{M}(p,d_{j})\end{array}\right)

must exist, and

lim⁡n→∞lim⁡p→∞Prob⁡A∈Mat⁡n(Zp)(∣coker⁡(Pj(A))∣=pdjkjtextforall(Pˉ1,…,Pˉr)∈∏j=1rM(p,dj))=∏j=1re−1/dj(1/dj)kjkj!.\lim_{n\to\infty}\lim_{p\to\infty}\operatorname{Prob}_{A\in\operatorname{Mat}_{n}(\mathbb{Z}_{p})}\left(\begin{array}{c}|\operatorname{coker}(P_{j}(A))|=p^{d_{j}k_{j}}\\text{for all }(\bar{P}_{1},\dots,\bar{P}_{r})\in\prod_{j=1}^{r}\mathcal{M}(p,d_{j})\end{array}\right)=\prod_{j=1}^{r}\frac{e^{-1/d_{j}}(1/d_{j})^{k_{j}}}{k_{j}!}.

This conjecture generalizes the preceding theorem, whose limiting probability for all the cokernels to be trivial is ∏j=1re−1/dj\prod_{j=1}^{r}e^{-1/d_{j}}. The claimed formula is the joint distribution of independent Poisson random variables with means 1/d1,…,1/dr1/d_{1},\dots,1/d_{r}. The authors report little empirical evidence and invite further examples supporting or disproving it, so its status remains open.

References

Primary source

Gilyoung Cheong, Jungin Lee, Hayan Nam and Myungjun Yu, “Jordan–Landau theorem for matrices over finite fields”, arXiv:2005.07846 (2022).

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.