Displaying similar documents to “On the set of solutions of the system x 1 + x 2 + x 3 = 1 , x 1 x 2 x 3 = 1 ”

Linear integral equations in the space of regulated functions

Milan Tvrdý (1998)

Mathematica Bohemica

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n this paper we investigate systems of linear integral equations in the space 𝔾 L n of n -vector valued functions which are regulated on the closed interval [ 0 , 1 ] (i.e. such that can have only discontinuities of the first kind in [ 0 , 1 ] ) and left-continuous in the corresponding open interval ( 0 , 1 ) . In particular, we are interested in systems of the form x(t) - A(t)x(0) - 01B(t,s)[d x(s)] = f(t), where f ∈ 𝔾 L n , the columns of the n × n -matrix valued function A belong to 𝔾 L n , the entries of B ( t , . ) have a bounded variation...

Circular distance in directed graphs

Bohdan Zelinka (1997)

Mathematica Bohemica

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Circular distance d ∘ ( x , y ) between two vertices x , y of a strongly connected directed graph G is the sum d ( x , y ) + d ( y , x ) , where d is the usual distance in digraphs. Its basic properties are studied.

Spectral properties of fourth order differential operators

Ondřej Došlý, Roman Hilscher (1997)

Mathematica Bohemica

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Necessary and sufficient conditions for discreteness and boundedness below of the spectrum of the singular differential operator ℓ ( y ) ≡ 1 w ( t ) ( r ( t ) y ) , t ∈ [ a , ∞ ) are established. These conditions are based on a recently proved relationship between spectral properties of ℓ and oscillation of a certain associated second order differential equation.

Dominating functions of graphs with two values

Bohdan Zelinka (1998)

Mathematica Bohemica

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The Y -domination number of a graph for a given number set Y was introduced by D. W. Bange, A. E. Barkauskas, L. H. Host and P. J. Slater as a generalization of the domination number of a graph. It is defined using the concept of a Y -dominating function. In this paper the particular case where Y = { 0 , 1 / k } for a positive integer k is studied.