The Anticenter and Reflection Line of a Cyclic Quadrilateral

Csiba, Peter and Donnelly, John and Németh, László (2025) The Anticenter and Reflection Line of a Cyclic Quadrilateral. INTERNATIONAL ELECTRONIC JOURNAL OF GEOMETRY, 18 (2). pp. 403-414. ISSN 1307-5624

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Abstract

The Simson point S of a quadrilateral Q is the point for which the pedal polygon of Q with respect to S degenerates into a single line, called the Simson line. If we reflect the Simson point in the lines containing the sides of Q, then we get another line that is parallel to the Simson line. We refer to this second line as the Reflection line of S. Ferrarello, Mammana, and Pennisi have conjectured that if Q is a cyclic quadrilateral that does not have parallel sides, then the reflection line of S passes through the anticenter of Q. We give a positive answer to this conjecture. We also give characterizations using the reflection line for a convex quadrilateral to be cyclic or to be semi-symmetric.

Tudományterület / tudományág

natural sciences > mathematics and computer sciences

Faculty

Not relevant

Institution

Soproni Egyetem

Item Type:	Article
SWORD Depositor:	Teszt Sword
Depositing User:	Csaba Horváth
Identification Number:	MTMT:36409701
Date Deposited:	04 Nov 2025 10:14
Last Modified:	04 Nov 2025 10:14
URI:	http://publicatio.uni-sopron.hu/id/eprint/3764

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