For fiber-commutative coherent configurations,we show that Krein parameters can be defined essentially uniquely.As a consequence,the general Krein condition reduces to positive semidefiniteness of finitely many matric...For fiber-commutative coherent configurations,we show that Krein parameters can be defined essentially uniquely.As a consequence,the general Krein condition reduces to positive semidefiniteness of finitely many matrices determined by the parameters of a coherent configuration.We mention its implications in the coherent configuration defined by a generalized quadrangle.We also simplify the absolute bound using the matrices of Krein parameters.展开更多
文摘For fiber-commutative coherent configurations,we show that Krein parameters can be defined essentially uniquely.As a consequence,the general Krein condition reduces to positive semidefiniteness of finitely many matrices determined by the parameters of a coherent configuration.We mention its implications in the coherent configuration defined by a generalized quadrangle.We also simplify the absolute bound using the matrices of Krein parameters.
