44 citations · 216 across the 16 of their papers we have counts for
11 papers · 2 filters
On distant-isomorphisms of projective lines
Andrea Blunck, Hans Havlicek
We determine all distant-isomorphisms between projective lines over semilocal rings. In particular, for those semisimple rings that do not have a simple component which is isomorph…
Radical parallelism on projective lines and non-linear models of affine spaces
Andrea Blunck, Hans Havlicek
We introduce and investigate an equivalence relation called "radical parallelism" on the projective line over a ring. It is closely related with the Jacobson radical of the underly…
On bijections that preserve complementarity of subspaces
Andrea Blunck, Hans Havlicek
The set of all -dimensional subspaces of a -dimensional vector space is endowed with two relations, complementarity and adjacency. We consider bijections from on…
Jordan homomorphisms and harmonic mappings
Andrea Blunck, Hans Havlicek
We show that each Jordan homomorphism of rings gives rise to a harmonic mapping of one connected component of the projective line over into the projective line over $…
The Dual of a Chain Geometry
Andrea Blunck, Hans Havlicek
We introduce and discuss the dual of a chain geometry. Each chain geometry is canonically isomorphic to its dual. This allows us to show that there are isomorphisms of chain geomet…
The Connected Components of the Projective Line over a Ring
Andrea Blunck, Hans Havlicek
The main result of the present paper is that the projective line over a ring is connected with respect to the relation "distant" if, and only if, is a -ring.