Let ψm be the smallest strong pseudoprime to the first m prime bases. This value is known for 1 ≤ m ≤ 11. We extend this by finding ψ12 and ψ13. We also present an algorithm to find all integers n ≤ B that are strong pseudoprimes to the first m prime bases; with a reasonable heuristic assumption we can show that it takes at most B2/3+o(1) time.

Let p be a prime k|p−1, t = (p−1)/k and γ(k, p) be the minimal value of s such that every number is a sum of s k-th powers (mod p). We prove Heilbronn’s conjecture that γ(k, p) k1/2 for t > 2. More generally we show that for any positive integer q, γ(k, p) ≤ C(q)k1/q for φ(t) ≥ q. A comparable lower bound is also given. We also establish exact values for γ(k, p) when φ(t) = 2. For instance, whe...

If D = (V,A) is a digraph, its competition hypergraph CH(D) has the vertex set V and e ⊆ V is an edge of CH(D) iff |e| ≥ 2 and there is a vertex v ∈ V , such that e = {w ∈ V |(w, v) ∈ A}. We tackle the problem to minimize the number of strong components in D without changing the competition hypergraph CH(D). The results are closely related to the corresponding investigations for competition gra...

We study a certain monotonicity property of ratios of means, which we call a strong inequality. These strong inequalities were recently shown to be related to the so-called relative metric. We also use the strong inequalities to derive new ordinary inequalities. The means studied are the extended mean value of Stolarsky, Gini’s mean and Seiffert’s mean.

Thermodynamic effects play an important role in the cavitation dynamics of cryogenics fluids. Such flows are characterized by strong variations in fluid properties with the temperature. A compressible, multiphase, one-fluid solver was developed to study and to predict thermodynamic effects in cavitating flows. To close the system, a cavitation model is proposed to capture metastable behaviours ...

Let X be a reflexive Banach space which has a weakly sequentially continuous duality mapping. In this paper, we consider the following viscosity approximation sequence x n λ n fx n 1−λ n T n x n , where λ n ∈ 0, 1, {T n } is a uniformly asymptotically regular sequence, and f is a weakly contractive mapping. Strong convergence of the sequence {x n } is proved.

In west coast groundfish stock assessments, biological productivity is largely defined by a single parameter, i.e., steepness (h) of the Beverton-Holt spawner-recruit curve, which ranges from 0.20 (no compensation) to 1.00 (complete compensation). A steepness of 0.20 implies no latent surplus production and a total lack of resilience to the effects of exploitation, whereas a value of 1.0 implie...

Implementation theory tackles the following problem: given a social choice correspondence, find a decentralized mechanism such that for every constellation of the individuals’ preferences, the set of outcomes in equilibrium is exactly the set of socially optimal alternatives (as specified by the correspondence). In this paper we are concerned with implementation by mediated equilibrium; under s...

Implementation theory tackles the following problem: given a social choice correspondence, find a decentralized mechanism such that for every constellation of the individuals’ preferences, the set of outcomes in equilibrium is exactly the set of socially optimal alternatives (as specified by the correspondence). In this paper we are concerned with implementation by mediated equilibrium; under s...

A prime p satisfying the congruence 2p−1 ≡ 1 (mod p) is called a Wieferich prime. Although the number of Wieferich primes is believed to be infinite, the only ones that have been discovered so far are 1093 and 3511. This paper describes a search for further solutions. The search was conducted via a large scale Internet based computation. The result that there are no new Wieferich primes less th...