Zobrazeno 1 - 10
of 487
pro vyhledávání: '"Lafont J"'
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
Autor:
Lafont, J.-F., McReynolds, D. B.
Publikováno v:
Publicacions Matemàtiques, 2019 Jan 01. 63(1), 183-218.
Externí odkaz:
https://www.jstor.org/stable/26860737
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