Zobrazeno 1 - 10
of 162
pro vyhledávání: '"Lafont, J P"'
Publikováno v:
Michigan Math. J. 68 (2019), pgs. 251--275
We study closed non-positively curved Riemannian manifolds $M$ which admit `fat $k$-flats': that is, the universal cover $\tilde M$ contains a positive radius neighborhood of a $k$-flat on which the sectional curvatures are identically zero. We inves
Externí odkaz:
http://arxiv.org/abs/1704.00857
Publikováno v:
Duke Math. J. 161, no. 1 (2012), 1-28
We construct examples of smooth 4-dimensional manifolds M supporting a locally CAT(0)-metric, whose universal cover X satisfy Hruska's isolated flats condition, and contain 2-dimensional flats F with the property that the boundary at infinity of F de
Externí odkaz:
http://arxiv.org/abs/1002.4235
Autor:
Francaviglia, S., Lafont, J. -F.
Publikováno v:
Indiana Univ. Math. J. 59 (2010), pgs. 395-415
For a k-flat F inside a locally compact CAT(0)-space X, we identify various conditions that ensure that F bounds a (k+1)-dimensional half flat in X. Our conditions are formulated in terms of the ultralimit of X. As applications, we obtain (1) constra
Externí odkaz:
http://arxiv.org/abs/0912.1172
Publikováno v:
Math. Proc. Cambridge Philos. Soc. 148 (2010), pgs. 193-226
For a finite volume geodesic polyhedron P in hyperbolic 3-space, with the property that all interior angles between incident faces are integral submultiples of Pi, there is a naturally associated Coxeter group generated by reflections in the faces. F
Externí odkaz:
http://arxiv.org/abs/0904.0054
Autor:
Lafont, J. -F.
Publikováno v:
Publ. Mat. 53 (2009), pgs. 515-525
We provide a strengthening of Jordan separation, to the setting of maps from a compact topological space X into a sphere, where the source space X is not necessarily a codimension one sphere, and the map is not necessarily injective.
Comment: 8
Comment: 8
Externí odkaz:
http://arxiv.org/abs/0807.5139
Autor:
Francaviglia, S., Lafont, J. -F.
Given a geodesic inside a simply-connected, complete, non-positively curved Riemannian (NPCR) manifold M, we get an associated geodesic inside the asymptotic cone Cone(M). Under mild hypotheses, we show that if the latter is contained inside a bi-Lip
Externí odkaz:
http://arxiv.org/abs/0801.3636
Autor:
Lafont, J. -F., Ortiz, I. J.
Publikováno v:
J. London Math. Soc. 79 (2009), pgs. 309-322
For a group G that splits as an amalgamation of A and B over a common subgroup C, there is an associated Waldhausen Nil-group, measuring the "failure" of Mayer-Vietoris for algebraic K-theory. Assume that (1) the amalgamation is acylindrical, and (2)
Externí odkaz:
http://arxiv.org/abs/0711.2533
Autor:
Lafont, J. -F., Ortiz, I. J.
Publikováno v:
Comment. Math. Helv. 84 (2009), pgs. 297-337
A hyperbolic 3-simplex reflection group is a Coxeter group arising as a lattice in the isometry group of hyperbolic 3-space, with fundamental domain a geodesic simplex (possibly with some ideal vertices). The classification of these groups is known,
Externí odkaz:
http://arxiv.org/abs/0705.0844
Autor:
Lafont, J. -F., Ortiz, I. J.
Publikováno v:
Forum Math. 20 (2008), pgs. 445-455
We prove that the Waldhausen Nil-group associated to a virtually cyclic groups that surjects onto the infinite dihedral group vanishes if and only if the corresponding Farrell Nil-group associated to the canonical index two subgroup is trivial. The p
Externí odkaz:
http://arxiv.org/abs/math/0609711
Autor:
Lafont, J. -F., Schmidt, B.
Publikováno v:
Geom. Topol. 11 (2007) 867-887
We study compact Riemannian manifolds for which the light between any pair of points is blocked by finitely many point shades. Compact flat Riemannian manifolds are known to have this finite blocking property. We conjecture that amongst compact Riema
Externí odkaz:
http://arxiv.org/abs/math/0607789