In this book we do a survey of the problem of finding suitable admissibility conditions on the parameters of strongly regular graphs and add our own contribution to the area. The matrix space spanned by the identity matrix and the adjacency matrix of a strongly regular graph is an Euclidean Jordan algebra with rank three. In this environment the Krein parameters of a strongly regular graph are generalized and some conditions on the parameters of a strongly regular graph are deduced. The results obtained were directly applied to the Krein parameters of the more general structures given by symmetric association schemes with any number of classes.

Vasco Mano holds a PhD in Applied Mathematics with distinction at the University of Porto in 2013. His research widely published and presented internationally is centered in spectral graph theory. Luís Vieira is currently assistant professor at the Faculty of Engineering of Oporto, Portugal. His research focuses mainly on algebra and combinatorics.