Combinatorial Mathematics V.

Subgroup theorems and graphs.- Counting unlabeled acyclic digraphs.- Golay sequences.- The knotted hexagon.- On skew room squares.- Some new constructions for orthogonal designs using circulants.- A note on asymptotic existence results for orthogonal designs.- The spectrum of a graph.- Latin squares composed of four disjoint subsquares.- The semi-stability of lexicographic products.- On rings of circuits in planar graphs.- Sum-free sets in loops.- Groups with stable graphs.- A problem in the design of electrical circuits, a generalized subadditive inequality and the recurrence relation j(n,m)=j([n/2],m)+j([n+1/2],m)+j(n,m-1).- Orthogonal designs in order 24.- A schröder triangle: Three combinatorial problems.- A combinatorial approach to map theory.- On quasi-multiple designs.- A generalisation of the binomial coefficients.