12 citations · 36 across the 12 of their papers we have counts for
13 papers
Classification of thin Jordan schemes
Mikhail Muzychuk, Christian Pech, Andrew Woldar
Jordan schemes generalize association schemes in a similar way as Jordan algebras generalize the associative ones. It is well-known that association schemes of maximal rank are in…
The classification of homomorphism homogeneous oriented graphs
Bojana Pavlica, Christian Pech, Maja Pech
The modern theory of homogeneous structures begins with the work of Roland Fraïssé. The theory developed in the last seventy years is placed in the border area between combinatoric…
Echeloned Spaces
Maxime Gheysens, Bojana Pavlica, Christian Pech +2
We introduce the notion of echeloned spaces - an order-theoretic abstraction of metric spaces. The first step is to characterize metrizable echeloned spaces. It turns out that morp…
Homogeneous ultrametric structures
W. Kubiś, Ch. Pech, M. Pech
We develop the theory of homogeneous Polish ultrametric structures. Our starting point is a Fraisse class of finite structures and the crucial tool is the universal homogeneous epi…
On a family of highly regular graphs by Brouwer, Ivanov, and Klin
Christian Pech, Maja Pech
Highly regular graphs for which not all regularities are explainable by symmetries are fascinating creatures. Some of them like, e.g., the line graph of W.~Kantor's non-classical $…
Reconstructing the topology of the elementary self-embedding monoids of countable saturated structures
Christian Pech, Maja Pech
Every transformation monoid comes equipped with a canonical topology-the topology of pointwise convergence. For some structures, the topology of the endomorphism monoid can be reco…
Polymorphism clones of homogeneous structures (Universal homogeneous polymorphisms and automatic homeomorphicity)
Christian Pech, Maja Pech
Every clone of functions comes naturally equipped with a topology---the topology of pointwise convergence. A clone is said to have automatic homeomorphicity with res…
On automatic homeomorphicity for transformation monoids
Christian Pech, Maja Pech
Transformation monoids carry a canonical topology --- the topology of point-wise convergence. A closed transformation monoid is said to have automatic homeomorphicit…
On highly regular strongly regular graphs
Christian Pech
In this paper we unify several existing regularity conditions for graphs, including strong regularity, -isoregularity, and the -vertex condition. We develop an algebraic comp…
On polymorphism-homogeneous relational structures and their clones
Christian Pech, Maja Pech
A relational structure is homomorphism-homogeneous if every homomorphism between finite substructures extends to an endomorphism of the structure. This notion was introduced recent…
Towards a Ryll-Nardzewski-type Theorem for weakly oligomorphic structures
Christian Pech, Maja Pech
A structure is called weakly oligomorphic if it realizes only finitely many n-ary positive existential types for every n. The goal of this paper is to show that the notions of homo…
Universal homomorphisms, universal structures, and the polymorphism clones of homogeneous structures
Christian Pech, Maja Pech
Using a categorial version of Fraïssé's theorem due to Droste and Göbel, we derive a criterion for a comma-category to have universal homogeneous objects. As a first application we…
Universal homogeneous constraint structures and the hom-equivalence classes of weakly oligomorphic structures
Christian Pech, Maja Pech
We derive a new sufficient condition for the existence of ω-categorical universal structures in classes of relational structures with constraints, augmenting results by Cherlin, Sh…