Zobrazeno 1 - 10
of 116
pro vyhledávání: '"Löwen, Rainer"'
Autor:
Löwen, Rainer
Publikováno v:
Adv. Geom. 22, No. 4, 525-539 (2022)
We describe the development of the mathematics of Helmut R. Salzmann (3. 11. 1930 -- 8. 3. 2022) and the main difficulties he was facing, documenting his lifelong productivity and his far reaching influence. We include a comprehensive bibliography of
Externí odkaz:
http://arxiv.org/abs/2310.09209
A locally compact stable plane of positive topological dimension will be called semiaffine if for every line $L$ and every point $p$ not in $L$ there is at most one line passing through $p$ and disjoint from $L$. We show that then the plane is either
Externí odkaz:
http://arxiv.org/abs/2309.00360
Autor:
Löwen, Rainer
Publikováno v:
Advances in Geometry 22 (4), 525 -- 539 (2022)
Using the Klein correspondence, regular parallelisms of PG(3,R) have been described by Betten and Riesinger in terms of a dual object, called a hyperflock determining (hfd) line set. In the special case where this set has a span of dimension 3, a sec
Externí odkaz:
http://arxiv.org/abs/2204.08001
Autor:
Löwen, Rainer, Steinke, Günter F.
Publikováno v:
Bull. Belg. Math. Soc. Simon Stevin 28, 305 - 326 (2021)
A regular parallelism of real projective 3-space PG(3,R) is an equivalence relation on the line space such that every class is equivalent to the set of 1-dimensional complex subspaces of a 2-dimensional complex vector space. We shall assume that the
Externí odkaz:
http://arxiv.org/abs/2101.06095
Autor:
Löwen, Rainer
Publikováno v:
Beitr. Algebra Geom. Journal Profile 60, No. 2, 333-337 (2019)
Betten and Riesinger constructed Parallelisms of $\mathop{\rm PG}(3,\mathbb R)$ with automorphism group $\mathop{\rm SO}(3,\mathbb R)$ by applying the reducible $\mathop{\rm SO}(3,\mathbb R)$-action to a rotational Betten spread. This was generalized
Externí odkaz:
http://arxiv.org/abs/1806.03862
Autor:
Löwen, Rainer
Publikováno v:
Journal of Geometry 110 No. 1, Paper No. 11, 15p. (2019)
We introduce topological parallelisms of oriented lines (briefly called oriented parallelisms). Every topological parallelism (of lines) on PG(3,R) gives rise to a parallelism of oriented lines, but we show that even the most homogeneous parallelisms
Externí odkaz:
http://arxiv.org/abs/1804.07615
Autor:
Löwen, Rainer
Publikováno v:
Innov. Incidence Geom. 17 (2019) 43-46
Betten and Riesinger have shown that Clifford parallelism on real projective space is the only topological parallelism that is left invariant by a group of dimension at least 5. We improve the bound to 4. Examples of different parallelisms admitting
Externí odkaz:
http://arxiv.org/abs/1702.03328
Autor:
Betten, Dieter, Löwen, Rainer
Publikováno v:
Results Math 72 (2017) 1021 - 1030
We conjecture that the automorphism group of a topological parallelism on real projective 3-space is compact. We prove that at least the identity component of this group is, indeed, compact.
Externí odkaz:
http://arxiv.org/abs/1702.02837
Publikováno v:
Math. Intell. Journal 29, No. 2, 49-58 (2007)
We investigate under which conditions a rectangular table can be placed with all four feet touching a continuous ground by turning it on the spot.
Comment: 17 pages, 7 figures
Comment: 17 pages, 7 figures
Externí odkaz:
http://arxiv.org/abs/math/0511490
Publikováno v:
Proceedings of the American Mathematical Society, 2010 Jan 01. 138(1), 323-332.
Externí odkaz:
https://www.jstor.org/stable/40590622
