13,448 research outputs found

    An algorithm for determining copositive matrices

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    In this paper, we present an algorithm of simple exponential growth called COPOMATRIX for determining the copositivity of a real symmetric matrix. The core of this algorithm is a decomposition theorem, which is used to deal with simplicial subdivision of T^−={y∈Δm∣βTy≤0}\hat{T}^{-}=\{y\in \Delta_{m}| \beta^Ty\leq 0\} on the standard simplex Δm\Delta_m, where each component of the vector β\beta is -1, 0 or 1.Comment: 15 page

    Hyperquadratic continued fractions over a finite field of odd characteristic with partial quotients of degree 1

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    In 1986, some examples of algebraic, and nonquadratic, power series over a finite prime field, having a continued fraction expansion with partial quotients all of degree one, were discovered by W. Mills and D. Robbins. In this note we show how these few examples are included in a very large family of continued fractions for certain algebraic power series over an arbitrary finite field of odd characteristic

    Triple Derivations and Triple Homomorphisms of Perfect Lie Superalgebras

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    In this paper, we study triple derivations and triple homomorphisms of perfect Lie superalgebras over a commutative ring RR. It is proved that, if the base ring contains 12\frac{1}{2}, LL is a perfect Lie superalgebra with zero center, then every triple derivation of LL is a derivation, and every triple derivation of the derivation algebra Der(L) Der (L) is an inner derivation. Let L, L′L,~L^{'} be Lie superalgebras over a commutative ring RR, the notion of triple homomorphism from LL to L′L^{'} is introduced. We proved that, under certain assumptions, homomorphisms, anti-homomorphisms, and sums of homomorphisms and anti-homomorphisms are all triple homomorphisms.Comment: 12pages in Indagationes Mathematicae, 201
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