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Nombres de racines d’un polynôme entier modulo q

Monique Branton, Olivier Ramaré (1998)

Journal de théorie des nombres de Bordeaux

Nous montrons que l’ensemble des racines modulo une puissance d’un nombre premier d’un polynôme à coefficients entiers de degré d est une union d’au plus d progressions arithmétiques de modules assez grands. Nous en déduisons une majoration du nombre de ses racines dans un intervalle réel court.

On a congruence of Emma Lehmer related to Euler numbers

John B. Cosgrave, Karl Dilcher (2013)

Acta Arithmetica

A congruence of Emma Lehmer (1938) for Euler numbers E p - 3 modulo p in terms of a certain sum of reciprocals of squares of integers was recently extended to prime power moduli by T. Cai et al. We generalize this further to arbitrary composite moduli n and characterize those n for which the sum in question vanishes modulo n (or modulo n/3 when 3|n). Primes for which E p - 3 0 ( m o d p ) play an important role, and we present some numerical results.

On a connection of number theory with graph theory

Lawrence Somer, Michal Křížek (2004)

Czechoslovak Mathematical Journal

We assign to each positive integer n a digraph whose set of vertices is H = { 0 , 1 , , n - 1 } and for which there is a directed edge from a H to b H if a 2 b ( m o d n ) . We establish necessary and sufficient conditions for the existence of isolated fixed points. We also examine when the digraph is semiregular. Moreover, we present simple conditions for the number of components and length of cycles. Two new necessary and sufficient conditions for the compositeness of Fermat numbers are also introduced.

On a linear homogeneous congruence

A. Schinzel, M. Zakarczemny (2006)

Colloquium Mathematicae

The number of solutions of the congruence a x + + a k x k 0 ( m o d n ) in the box 0 x i b i is estimated from below in the best possible way, provided for all i,j either ( a i , n ) | ( a j , n ) or ( a j , n ) | ( a i , n ) or n | [ a i , a j ] .

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