# Does the parameters $d, a, b$ uniquely determine a strongly regular graph?

The existence is not guanranteed of a strongly regular graph, $d$-regular, every pair of adjacent vertices having $a$ common neighbors, every pair of vertices not adjacent having $b$ common neighbors. But if it does exist for a set of parameters, should the graph ,up to isomorphism, be unique?

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 The tag graph is intended for questions about graphs of functions, see the tag-wiki and the tag-excerpt. (The tag-excerpt is also shown when you are adding a tag to a question.) There is a separate tag for graph-theory. – Martin Sleziak Mar 12 at 19:17

No. For instance, there are $15$ different Paulus graphs with parameters $(25, 12, 5, 6)$. For more information on strongly regular graphs, be sure to check Andries Brouwer's database and lecture notes.