Perturbations of centre-fixing dynamical systems.
Phantom maps and purity in modular representation theory, I
Let k be a field and G a finite group. By analogy with the theory of phantom maps in topology, a map f : M → ℕ between kG-modules is said to be phantom if its restriction to every finitely generated submodule of M factors through a projective module. We investigate the relationships between the theory of phantom maps, the algebraic theory of purity, and Rickard's idempotent modules. In general, adding one to the pure global dimension of kG gives an upper bound for the number of phantoms we need...
Phénomène de cutoff pour certaines marches aléatoires sur le groupe symétrique
The main purpose of this paper is to exhibit the cutoff phenomenon, studied by Aldous and Diaconis [AD]. Let denote a transition kernel after k steps and π be a stationary measure. We have to find a critical value for which the total variation norm between and π stays very close to 1 for , and falls rapidly to a value close to 0 for with a fall-off phase much shorter than . According to the work of Diaconis and Shahshahani [DS], one can naturally conjecture, for a conjugacy class with...
Pinned-flags of some operations on fuzzy subgroups.
Plane and layer symmetry groups
Plane and layer symmetry groups
Plane curves and their fundamental groups: Generalizations of Uludağ's construction.
Plane curves associated to character varieties of 3-manifolds.
Plane Motion Groups and Virtual Poincaré Duality of Dimension Two.
Platitude du module universel pour en caractéristique non banale
Soient un corps -adique, . Pour un caractère de l’algèbre de Hecke sphérique de sur un anneau commutatif , on introduit à la suite de Serre une représentation lisse de sur qui gouverne la théorie des représentations non ramifiées de sur . Nous prouvons que est plat sur et que si est inversible dans , alors pour tout sous-groupe compact ouvert suffisament petit de , le module est libre de rang fini sur . Ceci était conjecturé par Lazarus. Comme corollaire, nous obtenons...
Platonic triangles of groups.
Plenary stable quasigroups
Some results are obtained for quasigroups in which the operation of iterated squaring always leads to stability irrespective of the initial element.
P-localization of some classes of groups.
The aim for the present paper is to study the theory of P-localization of a group in a category C such that it contains the category of the nilpotent groups as a full sub-category. In the second section we present a number of results on P-localization of a group G, which is the semi-direct product of an abelian group A with a group X, in the category G of all groups. It turns out that the P-localized (GP) is completely described by the P-localized XP of X, A and the action w of X on A. In the third...
Plongement d'un groupoïde médian dans le groupoïde multiplicatif d'un semi-anneau médian
Plongements d'espaces symétriques algébriques : une classification
Plongements quasiisométriques du groupe de Heisenberg dans , d’après Cheeger, Kleiner, Lee, Naor
Bref survol du théorème de non-plongement de J. Cheeger et B. Kleiner pour le groupe d’Heisenberg dans .
Plus grand groupe image homomorphe et isotone d'un monoïde ordonné : caractérisations des anneaux «clos»
p-Nilpotence, classifying space indecomposability, and other properties of almost all finite groups.
P-nilpotent completion is not idempotent.
Let P be an arbitrary set of primes. The P-nilpotent completion of a group G is defined by the group homomorphism η: G → GP' where GP' = inv lim(G/ΓiG)P. Here Γ2G is the commutator subgroup [G,G] and ΓiG the subgroup [G, Γi−1G] when i > 2. In this paper, we prove that P-nilpotent completion of an infinitely generated free group F does not induce an isomorphism on the first homology group with ZP coefficients. Hence, P-nilpotent completion is not idempotent. Another important consequence of...
Poincaré Duality and Groups of Type (FP).