Reciprocal domains and Cohen-Macaulay -complexes in .
Reconstructing Plane Sets from Projections.
Reduction Theory for Fuchsian Groups.
Regular hexagons associated to centroid sharing triangles.
Regular polygons
Regular polyhedra - old and new.
Regular Polyhedra - Old and New. (Short Communication).
Regular Polytopes from Twisted Coxeter Groups.
Rektifizierbare vierdimensionale Simplices.
Relations on lines as primitive notions for Euclidean geometry
Remark on "Planes with analogues to Eucledian angular bisectors".
Remarques au sujet d'une note de M. Collignon
Representation of curves of constant width in the hyperbolic plane.
Résolution graphique d'un système d'équations de premier degré
Rigidité des empilements infinis immergés proprement dans le plan et dans le disque
Rigidity and Energy.
Rotation du sous-espace invariant d’un endomorphisme symétrique de par une perturbation symétrique
Rotation indices related to Poncelet’s closure theorem
Let CRCr denote an annulus formed by two non-concentric circles CR, Cr in the Euclidean plane. We prove that if Poncelet’s closure theorem holds for k-gons circuminscribed to CRCr, then there exist circles inside this annulus which satisfy Poncelet’s closure theorem together with Cr, with ngons for any n > k.
Routh’s, Menelaus’ and Generalized Ceva’s Theorems
The goal of this article is to formalize Ceva’s theorem that is in the [8] on the web. Alongside with it formalizations of Routh’s, Menelaus’ and generalized form of Ceva’s theorem itself are provided.