Combinatorics and Graph Theory : Proceedings of the Symposium Held at the Indian Statistical Institute Calcutta February 25–29 1980 Diperfect Graphs Some new problems and results in Graph Theory and other branches of Combinatorial Mathematics A form invariant multivariable polynomial representation of graphs Some combinatorial applications of the new linear programming algorithm In search of a complete invariant for graphs Affine triple systems Tables of two graphs Designs adjacency multigraphs and embeddings: A survey On the adjugate of a symmetrical balanced incomplete block design with =1 Characterization of potentially connected integer pair sequences Construction and combinatorial properties of orthogonal arrays with variable number of symbols in rows Construction of group divisible rotatable designs Some path length properties of graphs and digraphs 2 2 Perfect graphic degree sequences Characterization of forcibly outerplanar graphic sequences Characterization of potentially self complementary self converse degree pair sequences for digraphs Set reconstruction of chain sizes in a class of finite topologies Characterization of forcibly bipartite self complementary bipartitioned sequences A graph theoretical recurrence formula for computing the characteristic polynomial of a matrix A note concerning Acharya’s conjecture on a spectral measure of structural balance in a social system On permutation generating strings and rosaries Enumeration of labelled digraphs and hypergraphs Analysis of a spanning tree enumeration algorithm Binding number cycles and complete graphs A class of counterexamples to a conjecture on diameter critical graphs Reconstruction of a pair of connected graphs from their line concatenations On domination related concepts in Graph Theory The local central limit theorem for Stirling numbers of the second kind and an estimate for bell numbers A family of hypo hamiltonian generalized prisms Graphical cyclic permutation groups Orthogonal main effect plans with variable number of levels for factors On molecular and atomic matroids New inequalities for the parameters of an association scheme On the (4–3) regular subgraph conjecture Enumeration of Latin rectangles via SDR’s Nearly line regular graphs and their reconstruction On reconstructing separable digraphs Degree sequences of cacti A survey of the theory of potentially P graphic and forcibly P graphic degree sequences Towards a theory of forcibly hereditary P graphic sequences The minimal forbidden subgraphs for generalized line graphs Spectral characterization of the line graph of K  n Balanced arrays from association schemes and some related results Some further combinatorial and constructional aspects of generalized Youden designs Maximum degree among vertices of a non Hamiltonian homogeneously traceable graph.