caa a22 4500 445813431 CHVBK 20180317145219.0 cr unu---uuuuu 170323e20111201xx s 000 0 eng 10.1007/s00022-011-0095-x doi (NATIONALLICENCE)springer-10.1007/s00022-011-0095-x Horváth Á. Department of Geometry, Budapest University of Technology and Economics, 1521, Budapest, Hungary aut Projection pencils of quadrics and Ivory's theorem [Elektronische Daten] [Á. Horváth] Using selfadjoint regular endomorphisms, the authors of Stachel and Wallner (Sib Math J 45(4):785-794, 2004) defined, for an indefinite inner product, a variant of the notion of confocality for the Euclidean space. Our aim is to give a definition that is a common generalization of the usual confocality, and the variant in Stachel and Wallner (Sib Math J 45(4):785-794, 2004). We use this definition to prove a more general form of Ivory's theorem. Springer Basel AG, 2011 Indefinite inner product nationallicence Ivory's theorem nationallicence projection pencils of quadrics nationallicence Journal of Geometry SP Birkhäuser Verlag Basel 102/1-2(2011-12-01), 85-101 0047-2468 102:1-2<85 2011 102 22 https://doi.org/10.1007/s00022-011-0095-x text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00022-011-0095-x text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Horváth Á. Department of Geometry, Budapest University of Technology and Economics, 1521, Budapest, Hungary aut NATIONALLICENCE 773 0- Journal of Geometry SP Birkhäuser Verlag Basel 102/1-2(2011-12-01), 85-101 0047-2468 102:1-2<85 2011 102 22 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer