| Popis: |
A non-empty k -regular graph Γ on n vertices is called a Deza graph if there exist constants b and a ( b ≥ a ) such that any pair of distinct vertices of Γ has either b or a common neighbours. The quantities n , k , b , and a are called the parameters of Γ and are written as the quadruple ( n , k , b , a ) . If a Deza graph has diameter 2 and is not strongly regular, then it is called a strictly Deza graph. In the present paper, we investigate strictly Deza graphs whose parameters ( n , k , b , a ) satisfy the conditions k = b + 1 and k ( k − 1 ) − a ( n − 1 ) b − a > 1 . |
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