Grishkov and Logachev have asked (Problem 1.4 of their recent survey) whether, for a fixed finite field F_q, the analytic ranks of the twists of the Carlitz module are bounded. We answer this in the negative for every q>= 3. For q = p^s and n>= 1 put P_{q,n} = (theta^(q^n) - theta)^(q-2). We show that the directed graph of the matrix M(P_{q,n},1,k) of Grishkov-Logachev has a completely explicit set of circuits: they are pairwise disjoint, none of them meets an entry involving t, and they are in bijection with the orbits of E^n under cyclic rotation, where E is the set of l in [0,q-2] with p not dividing l+1. Consequently L(C_P, t, T) does not depend on t, it factors as a product of one term 1 - wt(nu) T^per(nu) per orbit, and the analytic rank equals the sum of p^(v_p(per(nu))) over the orbits of weight 1. When n is a power of p this equals (q/p)^n (p-1)^(n-1), which is unbounded. The argument also answers questions 3.6.1 to 3.6.4 of the survey for this family.
Let $f_m(x_0,\ldots,x_{2m-2}) =\det(x_{i+j})_{0\leq i,j\leq m-1}$ be the determinant of the generic symmetric Hankel matrix of size $m$. We determine its global Bernstein--Sato polynomial. The proof combines the nearby cycles of the corresponding secant hypersurface with an explicit Archimedean zeta integral over the c...
Let K be a field containing Q, let Γ be the ring of all functions N+ → K under Dirichlet convolution, and let Γn be its truncation to functions supported on [1, n]. In [9] it was shown that Γn is a polynomial ring modulo a monomial ideal In which is stable after reversing the order of the variables, and the Poincaré–Be...
Let $\mathcal P_k=\mathbb F_2[x_1,\ldots,x_k]$ be the polynomial algebra over the prime field $\mathbb F_2$, viewed as an unstable module over the mod-$2$ Steenrod algebra $\mathcal A$. The well-known Peterson hit problem asks for a minimal set of generators for the $\mathcal A$-module $\mathcal P_k$. This is equivalen...
Let N be a sufficiently large odd integer. We study the representation of a large integer m N^k as a sum of m almost equal k-th powers of primes, where the common distribution scale is at least N^theta. Assuming the Generalized Riemann Hypothesis (GRH), we prove that for any epsilon>0 one may take theta>1/2, provided t...
We prove the sign-isotypic components of the coinvariant rings $R_n^{(2,1)}$ and $R_n^{(2,0)} \otimes R_n^{(0,1)}$ are isomorphic and show that the triply-graded multiplicity of this sign character is the Schr\"oder polynomial $S_n(q,t,a)$, divided by $1+a$. This settles the sign-character component of a conjecture of...
Nicolle González, John Lentfer, Hanna Mularczyk· 0 citations
Let H be a subgroup of a finite group G, and put n = [G:H]>1. If p is the least prime divisor of n, we prove that the number of subgroups K with H<= K<= G is less than c(p) n^((log_p n)/4). Here c(p) is the product of (1 - p^(-j))^(-1) over all positive integers j, multiplied by the sum of p^(-z^2) over all integers z....
S. Palcoux, Pablo Spiga· 1 citation
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