Classification of general absolute planes by quasi-ends

Verfasser / Beitragende:
[Helmut Karzel, Silvia Pianta, Mahfouz Rostamzadeh, Sayed-Ghahreman Taherian]
Ort, Verlag, Jahr:
2015
Enthalten in:
Aequationes mathematicae, 89/3(2015-06-01), 863-872
Format:
Artikel (online)
ID: 605508577
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024 7 0 |a 10.1007/s00010-014-0283-5  |2 doi 
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245 0 0 |a Classification of general absolute planes by quasi-ends  |h [Elektronische Daten]  |c [Helmut Karzel, Silvia Pianta, Mahfouz Rostamzadeh, Sayed-Ghahreman Taherian] 
520 3 |a General (i.e. including non-continuous and non-Archimedean) absolute planes have been classified in different ways, e.g. by using Lambert-Saccheri quadrangles (cf. Greenberg, J Geom 12/1:45-64, 1979; Hartshorne, Geometry; Euclid and beyond, Springer, Berlin, 2000; Karzel and Marchi, Le Matematiche LXI:27-36, 2006; Rostamzadeh and Taherian, Results Math 63:171-182, 2013) or coordinate systems (cf. Pejas, Math Ann 143:212-235, 1961 and, for planes over Euclidean fields, Greenberg, J Geom 12/1:45-64, 1979). Here we consider the notion of quasi-end, a pencil determined by two lines which neither intersect nor have a common perpendicular (an ideal point of Greenberg, J Geom 12/1:45-64, 1979). The cardinality ω of the quasi-ends which are incident with a line is the same for all lines hence it is an invariant $${\omega_\mathcal{A}}$$ ω A of the plane $${\mathcal{A}}$$ A and can be used to classify absolute planes. We consider the case $${\omega_\mathcal{A}=0}$$ ω A = 0 and, for $${\omega_\mathcal{A} \geq 2}$$ ω A ≥ 2 (it cannot be 1) we prove that in the singular case $${\omega_\mathcal{A}}$$ ω A must be infinite. Finally we prove that for hyperbolic planes, ends and quasi-ends are the same, so $${\omega_\mathcal{A}=2}$$ ω A = 2 . 
540 |a Springer Basel, 2014 
690 7 |a Absolute Plane  |2 nationallicence 
690 7 |a Quasi-Parallel Line  |2 nationallicence 
690 7 |a Quasi-End  |2 nationallicence 
700 1 |a Karzel  |D Helmut  |u Zentrum Mathematik, T.U. München, 80290, München, Germany  |4 aut 
700 1 |a Pianta  |D Silvia  |u Dipartimento di Matematica e Fisica, Università Cattolica, Via Trieste, 17, 25121, Brescia, Italy  |4 aut 
700 1 |a Rostamzadeh  |D Mahfouz  |u Department of Mathematical Sciences, Isfahan University of Technology, 84156, Isfahan, Iran  |4 aut 
700 1 |a Taherian  |D Sayed-Ghahreman  |u Department of Mathematical Sciences, Isfahan University of Technology, 84156, Isfahan, Iran  |4 aut 
773 0 |t Aequationes mathematicae  |d Springer Basel  |g 89/3(2015-06-01), 863-872  |x 0001-9054  |q 89:3<863  |1 2015  |2 89  |o 10 
856 4 0 |u https://doi.org/10.1007/s00010-014-0283-5  |q text/html  |z Onlinezugriff via DOI 
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900 7 |a Metadata rights reserved  |b Springer special CC-BY-NC licence  |2 nationallicence 
908 |D 1  |a research-article  |2 jats 
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950 |B NATIONALLICENCE  |P 700  |E 1-  |a Karzel  |D Helmut  |u Zentrum Mathematik, T.U. München, 80290, München, Germany  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Pianta  |D Silvia  |u Dipartimento di Matematica e Fisica, Università Cattolica, Via Trieste, 17, 25121, Brescia, Italy  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Rostamzadeh  |D Mahfouz  |u Department of Mathematical Sciences, Isfahan University of Technology, 84156, Isfahan, Iran  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Taherian  |D Sayed-Ghahreman  |u Department of Mathematical Sciences, Isfahan University of Technology, 84156, Isfahan, Iran  |4 aut 
950 |B NATIONALLICENCE  |P 773  |E 0-  |t Aequationes mathematicae  |d Springer Basel  |g 89/3(2015-06-01), 863-872  |x 0001-9054  |q 89:3<863  |1 2015  |2 89  |o 10