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Existence and uniqueness of optimal matrix scalings
diagonal similarity scalings scaled singular value minimization irreducible matrices
2015/8/12
We show that the set of diagonal similarity scalings that minimize the scaled singular value of a matrix is nonempty and bounded if and only if the matrix that is being scaled is irreducible. For an i...
NON-EXISTENCE OF SINGULAR CYCLES IN AQUADRIC DIFFERENTIAL SYSTEM WITH FINE FOCUS OF ORDER THREE
Homodinic heteroclinic centre-focus cr
2007/12/17
The problem of existence or non-existence of singular cycles (or komoclinic loops and keteroclinic cydes as being termed in the modern literature of nonlinear dyndric systems) is one of the most impor...
EXISTENCE OF CONSISTENT ESTIMATES OF LINEAR REGRESSION COEFFICIENTS WHEN THE ERROR VARIANCES ARE UNEQUAL
Linear regression model consistency
2007/12/10
摘要 Consider the linear regression model Y_i=x_i′β+σ_ie_i,i=1,…,n,…, where E(e_i)=0, E(e_ie_j)=δ_(ij), 00. This paper shows that (i) if σ_i~2,i=1,2…, are known, then the necessary and sufficient condit...
ON THE EXISTENCE AND UNIQUENESS OF PERIODIC SOLUTIONS OF VOLTERRA INTEGRAL DIFFERENTIAL EQUATIONS
Periodic solutions Volterra integro-dif
2007/12/10
摘要 In this paper, we use the contraction principle and the Leray-Schauder principle to deal with the existence of periodic solutions of the Volterra integral differential equation. Some new existence ...
EXISTENCE AND UNIQUENESS OF ENDEMIC STATES FOR THE AGE-STRUCTURED SEIR EPIDEMIC MODEL
Age structure positive endemic state S
2007/8/7
An age-structured SEIR epidemic model of a vertically as well as horizontallytransmitted disease is investigated. Threshold results for the existence of endemicstates are established for most cases. U...
EXISTENCE OF SOLUTIONS FOR A CLASS OF SYSTEMS GOVERNED BY NONLINEAR DIFFERENTIAL INCLUSIONS
Existence dmerential inclusion multifu
2007/8/7
In this article we discuss the existence of solutions for a class of controlled systems governed by nonlinear differential inclusion where principal operator A is a nonlinear monotone operator. Using...
ON THE BOUNDEDNESS OF SOLUTIONS,EXISTENCE AND UNIQUENESS OF LIMIT CYCLES FOR A CLASS OF CUBIC DIFFERENTIAL SYSTEM
Boundedness of solutions limit cycle exi
2007/8/7
In this paper, we discuss the boundedness of the solutions, the existence and the uniqueness of the limit cycle of the following cubic differential system: x'=y, y'=-x+δy+a_2xy+a_4x+a_5x~2y. (*) We ob...