Subgroups of the (2,3,7) Triangle Group.
Subgroups of the modular group defined by a single linear congruence
Sublattices of certain Coxeter lattices
In this paper, we describe the sublattices of some lattices, extending previous results of [Ber]. Our description makes intensive use of graphs.
Subprincipal closed ideals in ßN.
Subrings in imaginary quadratic fields which are not universal for GE₂
Subsequence sums of zero-sum free sequences over finite abelian groups
Let G be a finite abelian group of rank r and let X be a zero-sum free sequence over G whose support supp(X) generates G. In 2009, Pixton proved that for r ≤ 3. We show that this result also holds for abelian groups G of rank 4 if the smallest prime p dividing |G| satisfies p ≥ 13.
Subsequences of binary recursive sequences
Subset sums avoiding quadratic nonresidues
Subset sums modulo a prime
Subspace in Hermitean Spaces of Countable Dimension. II.
Subspaces in Hermitean Spaces of Countable Dimension.
Substitution dynamical systems : algebraic characterization of eigenvalues
Substitution invariant cutting sequences
Substitution invariant sturmian bisequences
We prove that a Sturmian bisequence, with slope and intercept , is fixed by some non-trivial substitution if and only if is a Sturm number and belongs to . We also detail a complementary system of integers connected with Beatty bisequences.
Substitutions, abstract number systems and the space filling property
In this paper we study multi-dimensional words generated by fixed points of substitutions by projecting the integer points on the corresponding broken halfline. We show for a large class of substitutions that the resulting word is the restriction of a linear function modulo and that it can be decided whether the resulting word is space filling or not. The proof uses lattices and the abstract number system associated with the substitution.
Substitutions and 1/2-discrepancy of nθ + x
Substitutions commutatives de séries formelles
L’étude des systèmes dynamiques non archimédiens initiée par J. Lubin conduit à déterminer la ramification de séries à coefficients dans un corps fini , qui commutent entre elles pour la loi . Dans cet article nous traitons le cas des sous-groupes abéliens de qui correspondent par le foncteur corps de normes aux extensions abéliennes des extensions finies de , dont la ramification se stabilise dès le début.
Substitutions on two letters, cutting segments and their projections
In this paper we study the structure of the projections of the finite cutting segments corresponding to unimodular substitutions over a two-letter alphabet. We show that such a projection is a block of letters if and only if the substitution is Sturmian. Applying the procedure of projecting the cutting segments corresponding to a Christoffel substitution twice results in the original substitution. This induces a duality on the set of Christoffel substitutions.
Substitutions par des motifs en dimension 1
Une substitution est un morphisme de monoïdes libres : chaque lettre a pour image un mot, et l'image d'un mot est la concaténation des images de ses lettres. Cet article introduit une généralisation de la notion de substitution, où l'image d'une lettre n'est plus un mot mais un motif, c'est-à-dire un “mot à trous”, l'image d'un mot étant obtenue en raccordant les motifs correspondant à chacune de ses lettres à l'aide de règles locales. On caractérise complètement les substitutions par des motifs...
Substitutions with Cofinal Fixed Points
Let be a substitution over a 2-letter alphabet, say . If and begin with and respectively, has two fixed points beginning with and respectively.We characterize substitutions with two cofinal fixed points (i.e., which differ only by prefixes). The proof is a combinatorial one, based on the study of repetitions of words in the fixed points.