Displaying similar documents to “Certain comparative examinations of plane geometries according to Cayley-Klein.”

On some ideal related to the ideal (v 0 )

Piotr Kalemba (2015)

Open Mathematics


The ideal (v0) is known in the literature and is naturally linked to the structure [ω]ω. We consider some natural counterpart of the ideal (v0) related in an analogous way to the structure Dense(ℚ) and investigate its combinatorial properties. By the use of the notion of ideal type we prove that under CH this ideal is isomorphic to (v0).

A Construction of a Skewaffine Structure in Laguerre Geometry

Andrzej Matraś (2006)

Bulletin of the Polish Academy of Sciences. Mathematics


J. Andre constructed a skewaffine structure as a group space of a normally transitive group. In this paper his construction is used to describe the structure of the set of circles not passing through a point of a Laguerre plane. Sufficient conditions to ensure that this structure is a skewaffine plane are given.