Publications Repository - Gdańsk University of Technology

The Turán number ex(n,G) is the maximum number of edges in any n-vertex graph that does not contain a subgraph isomorphic to G. A wheel W_n is a graph on n vertices obtained from a C_{n−1} by adding one vertex w and making w adjacent to all vertices of the C_{n−1}. We obtain two exact values for small wheels: ex(n,W_5)=\lfloor n^2/4+n/2\rfloor, ex(n,W_7)=\lfloor n^2/4+n/2+1 \rfloor. Given that ex(n,W_6) is already known, this paper completes the spectrum for all wheels up to 7 vertices. In addition, we present the construction which gives us the lower bound ex(n,W_{2k+1})>\lfloor n^2/4 \rfloor + \lfloor n/2 \rfloor in general case.

Authors

• dr hab. Tomasz Dzido,
• mgr inż. Andrzej Jastrzębski link open in new tab