kroonograafid

Kroonograafid (also known as crown graphs or crown trees) are a type of mathematical graph structure used primarily in graph theory and combinatorics. The term originates from the study of planar graphs, which can be drawn on a plane without any edges crossing. A crown graph is a specific type of planar graph that resembles a "crown" or a circular arrangement of vertices connected in a particular pattern.

A crown graph is typically constructed by taking a cycle graph (a closed loop of vertices connected in sequence) and adding chords between non-adjacent vertices in a symmetric fashion. The simplest example is the Möbius–Kantor graph, which consists of two cycles of length *n* connected in a specific alternating manner. Crown graphs are often denoted as *Crown(n)*, where *n* represents the number of vertices in each cycle.

These graphs have been studied for their properties in graph theory, including connectivity, chromatic number, and independence number. Crown graphs exhibit interesting characteristics, such as being Hamiltonian (containing a cycle that visits each vertex exactly once) and having a specific structure that makes them useful in theoretical investigations. They also appear in the study of graph products, such as the Cartesian product and the strong product of graphs.

In addition to theoretical interest, crown graphs have applications in various areas of computer science, including network design, coding theory, and the analysis of algorithms. Their symmetric and structured nature makes them useful models for studying graph-related problems in discrete mathematics.

While crown graphs are not as commonly encountered in practical applications as other graph types, their study contributes to a deeper understanding of graph theory principles and their broader implications in mathematics and computer science.