This is the first exposition of the theory of quasi-symmetric designs, that is, combinatorial designs with at most two block intersection numbers. The authors aim to bring out the interaction among designs, finite geometries, and strongly regular graphs. The book starts with basic, classical material on designs and strongly regular graphs and continues with a discussion of some important results on quasi-symmetric designs. The later chapters include a combinatorial construction of the Witt designs from the projective plane of order four, recent results dealing with a structural study of...

Providing a unified exposition of the theory of symmetric designs with emphasis on recent developments, this volume covers the combinatorial aspects of the theory, giving particular attention to the construction of symmetric designs and related objects. The last five chapters are devoted to balanced generalized weighing matrices, decomposable symmetric designs, subdesigns of symmetric designs, non-embeddable quasi-residual designs, and Ryser designs. The book concludes with a comprehensive bibliography of over 400 entries. Detailed proofs and a large number of exercises make it suitable as a...