Theory of 2-structures. Part I: clans, basic subclasses, and morphisms
Theoretical Computer Science
Primitivity is hereditary for 2-structures
Theoretical Computer Science
Graph Theory With Applications
Graph Theory With Applications
Hi-index | 0.00 |
A subset X of a 2-structure (a reversible edge-colored directed graph) g is a clan, if X cannot be distinguished by colors from outside of X. We show that if g is primitive, i.e. it has no nontrivial clans, then there exists an edge e or an end vertex x such that when e or x is removed from g, the resulting 2-structure g′ remains primitive. We also present a composition result for the unstable 2-structures, which are those primitive 2-structures where a removal of any edge results in a nonprimitive 2-structure.