Abstract: The Wallace lines of a triangle in the affine-metric plane over $\bbR$ were studied by O. Giering [G]. This paper deals with the isotropic or galilean case [S] - which is not included in [G]. Essential means is the $\delta$-footpoint definition of J. Lang [L].
[L] Lang, J.: Zur isotropen Dreiecksgeometrie und zum Appolonischen Berührproblem in der isotropen Ebene. Ber. Math.-Stat. Sekt. Forschungszentrum Graz 20 (1983), 1-11.
[G] Giering, O.: Affine and projective generalization of Wallace lines. Journal for Geometry and Graphics 1 (1997), 119-133.
[S] Schröder, E. M.: Vorlesungen über Geometrie. Bd. 3: Metrische Geometrie. BI-Verlag, Mannheim 1992.
Keywords: isotropic plane, $\delta$-footpoint, Wallace lines
Classification (MSC2000): 51N25
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