Abstract
In this paper we introduce a new type of orthogonality for real normed planes which coincides with usual orthogonality in the Euclidean situation. With the help of this type of orthogonality we derive several characterizations of the Euclidean plane among all normed planes, all of them yielding also characteristic properties of inner product spaces among real normed linear spaces of dimensions d ⩾ 3.
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J. Alonso, H. Martini and Z. Mustafaev: On orthogonal chords in normed planes. To appear in Rocky Mountains J. Math.
D. Amir: Characterizations of Inner Product Spaces. Birkhäuser Verlag, Basel-Boston-Stuttgart, 1986.
E. Asplund and B. Grünbaum: On the geometry of Minkowski planes. Enseign. Math. 6 (1960), 299–306.
C. Benitez: Orthogonality in normed linear spaces: classification of the different concepts and some open problems. Revista Mat. Univ. Compl. Madrid 2 (1989), 53–57.
G. Birkhoff: Orthogonality in linear metric spaces. Duke Math. J. 1 (1935), 169–172.
J.E. Hofmann: Zur elementaren Dreiecksgeometrie in der komplexen Ebene. Enseign. Math. 4 (1958), 178–211.
R.C. James: Orthogonality in normed linear spaces. Duke Math. J. 12 (1945), 291–301.
R.C. James: Inner product in normed linear spaces. Bull. Amer. Math. Soc. 53 (1947), 559–566.
H. Martini: The three-circles theorem, Clifford configurations, and equilateral zonotopes (N.K. Artémiadis and N.K. Stephanidis, Thessaloniki, eds.). Proc. 4th Internat. Congr. Geometry (Thessaloniki, 1996), 1997, pp. 281–292.
H. Martini and M. Spirova: The Feuerbach circle and orthocentricity in normed planes. Enseign. Math. 53 (2007), 237–258.
H. Martini and M. Spirova: Clifford’s chain of theorems in strictly convex Minkowski planes. Publ. Math. Debrecen 72 (2008), 371–383.
H. Martini, K. J. Swanepoel and G. Weiss: The geometry of Minkowski spaces-a survey, Part I. Expositiones Math. 19 (2001), 97–142.
A. C. Thompson: Minkowski Geometry. Encyclopedia of Mathematics and its Applications, Vol. 63, Cambridge University Press, Cambridge, 1996.
G. Weiss: The concepts of triangle orthocenters in Minkowski planes. J. Geom. 74 (2002), 145–156.
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Research supported by Deutsche Forschungsgemeinschaft.
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Martini, H., Spirova, M. A new type of orthogonality for normed planes. Czech Math J 60, 339–349 (2010). https://doi.org/10.1007/s10587-010-0039-x
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DOI: https://doi.org/10.1007/s10587-010-0039-x
Keywords
- chordal orthogonality
- Feuerbach circle
- inner product space
- James orthogonality
- Minkowski plane
- normed linear space
- normed plane
- orthocentricity
- Wallace line