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Related papers: Poncelet Parabola Pirouettes

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A Circumconic passes through a triangle's vertices; an Inconic is tangent to the sidelines. We study the variable geometry of certain conics derived from the 1d family of 3-periodics in the Elliptic Billiard. Some display intriguing…

Dynamical Systems · Mathematics 2021-08-13 Dan Reznik , Ronaldo Garcia

We pose a monotonicity conjecture on the number of pseudo-triangulations of any planar point set, and check it on two prominent families of point sets, namely the so-called double circle and double chain. The latter has asymptotically $12^n…

Combinatorics · Mathematics 2009-07-07 Oswin Aichholzer , David Orden , Francisco Santos , Bettina Speckmann

We introduce several-dozen experimentally-found invariants of Poncelet N-periodics in the confocal ellipse pair (Elliptic Billiard). Recall this family is fully defined by two integrals of motion (linear and angular momentum), so any "new"…

Dynamical Systems · Mathematics 2021-08-13 Dan Reznik , Ronaldo Garcia , Jair Koiller

A Circumconic passes through a triangle's vertices. We define the Circumbilliard, a circumellipse to a generic triangle for which the latter is a 3-periodic. We study its properties and associated loci.

Dynamical Systems · Mathematics 2020-04-16 Dan Reznik , Ronaldo Garcia

Given a triangle, a trio of circumellipses can be defined, each centered on an excenter. Over the family of Poncelet 3-periodics (triangles) in a concentric ellipse pair (axis-aligned or not), the trio resembles a rotating propeller, where…

Metric Geometry · Mathematics 2021-08-13 Dominique Laurain , Daniel Jaud , Dan Reznik

Among a triangle's exparabolas (parabolas escribed to the triangle), three are distinguished by having locally maximal parameter. They are determined by a simple cubic equation and characterized by having axes that contain the triangle's…

Metric Geometry · Mathematics 2026-04-02 Martin Lukarevski , Hans-Peter Schröcker

We explore geometric and topological properties of 3d surfaces swept by Poncelet triangles, as well as tangles formed by associated points.

Geometric Topology · Mathematics 2022-01-25 Claudio Esperança , Ronaldo Garcia , Dan Reznik

The study of Diophantine triples taking values in linear recurrence sequences is a variant of a problem going back to Diophantus of Alexandria which has been studied quite a lot in the past. The main questions are, as usual, about existence…

Number Theory · Mathematics 2018-10-30 Clemens Fuchs , Christoph Hutle , Florian Luca

In condensed matter systems, the atoms, electrons or spins can sometimes arrange themselves in ways that result in unexpected properties but that cannot be detected by conventional experimental probes. Several historical and contemporary…

Materials Science · Physics 2021-06-01 Gabriel Aeppli , Alexander V. Balatsky , Henrik M. Rønnow , Nicola A. Spaldin

In the projective plane over a finite field of characteristic not equal to 2, we compute the probability that a randomly selected pair of distinct conics $(\mathscr{A},\mathscr{B})$, with $\mathscr{A}$ smooth or singular and $\mathscr{B}$…

Algebraic Geometry · Mathematics 2026-03-17 Milena Radnović , Ruzzel Ragas

Via simulation, we discover and prove curious new Euclidean properties and invariants of the Poncelet family of harmonic polygons.

Metric Geometry · Mathematics 2022-09-30 Ronaldo Garcia , Dan Reznik , Pedro Roitman

We present a new proof of the necessary and sufficient condition for the existence of a triangle that is simultaneously inscribed in a circle and circumscribed about a central conic (an ellipse or a hyperbola). In the limiting case where…

General Mathematics · Mathematics 2026-03-10 Vladimir Dragović , Mohammad Hassan Murad

The search for universality in random triangulations of manifolds, like those featuring in (Euclidean) Dynamical Triangulations, is central to the random geometry approach to quantum gravity. In case of the 3-sphere, or any other manifold…

Combinatorics · Mathematics 2022-03-31 Timothy Budd , Luca Lionni

We prove existence of three unique ``max-exparabolas'' to a triangle. Each of these parabolas is internally tangent to one edge and the two other sides. Among all like parabolas, it is characterized by having maximal parameter. We use this…

Metric Geometry · Mathematics 2026-04-02 Martin Lukarevski , Hans-Peter Schröcker

The following problem is treated: Characterizing the tangent cone and the equimultiple locus of a Puiseux surface (that is, an algebroid embedded surface admitting an equation whose roots are Puiseux power series), using a set of exponents…

Algebraic Geometry · Mathematics 2010-05-31 Jose M. Tornero

We continue the work begun in OEIS sequence A332636 which presents recursive sequences that have triangles that appear embedded in them. This paper i) generalizes the main result presented in A332636, ii) provides a complete set of…

Number Theory · Mathematics 2021-01-26 Russell Jay Hendel

The elements of a finite field of prime order canonically correspond to the integers in an interval. This induces an ordering on the elements of the field. Using this ordering, Kiss and Somlai recently proved interesting properties of the…

Combinatorics · Mathematics 2026-01-28 Sam Adriaensen , Zsuzsa Weiner

The Bernoulli numbers are fascinating and ubiquitous numbers, they occur in several domains of Mathematics like Number theory (FLT), Group theory, Calculus and even in Physics. Since Bernoulli's work, they are yet studied to understand…

Number Theory · Mathematics 2016-12-13 Abdelmoumène Zekiri , Farid Bencherif

We study the locus of the Circumcenter of Mass of Poncelet polygons, and the limit of the Center of Mass (when we consider the polygon as a "homogeneous lamina") for degenerate Poncelet polygons. We also provide a proof for one of Dan…

Metric Geometry · Mathematics 2020-04-14 Ana C. Chavez-Caliz

Envelopes of parameterized families of plane curves is an important topic, both for the mathematics involved and for its applications. Nowadays, it is generally studied in a technology-rich environment, and automated methods are developed…

Algebraic Geometry · Mathematics 2025-04-02 Thierry Dana-Picard , Daniel Tsirkin