Dorina Jibetean

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We consider the problem of minimizing a polynomial function on R n , known to be hard even for degree 4 polynomials. Therefore approximation algorithms are of interest. Lasserre [15] and Parrilo [23] have proposed approximating the minimum of the original problem using a hierarchy of lower bounds obtained via semidefinite programming relaxations. We propose(More)
We consider the problem of global minimization of rational functions on IR n (unconstrained case), and on an open, connected, semi-algebraic subset of IR n , or the (partial) closure of such a set (constrained case). We show that in the univariate case (n = 1), these problems have exact reformulations as semidefinite programming (SDP) problems, by using(More)
The problem of minimizing a polynomial function in several variables over R n is considered and an algorithm is given. When the polynomial has a minimum the algorithm returns the global minimum and nds at least one point in every connected component of the set of minimizers. A characterization of such points is given. When the polynomial does not have a(More)
A variety of problems in mathematical calculus can be solved by recursively applying a finite number of rules. Often, a generic solving strategy can be extracted and an interactive exercise system that emulates a tutor can be implemented. In this paper we show how software developed by us can be used to realize this interactivity. In particular, an(More)
We consider here the problem of minimizing a polynomial function on R n. The problem is known to be hard even for degree 4. Therefore approximation algorithms are of interest. Lasserre [11] and Parrilo [16] have proposed approximating the minimum of the original problem using a hierarchy of lower bounds obtained via semidefi-nite programming relaxations. We(More)
This section deals with our work on interactive mathematical documents that make use of the World Wide Web. These documents take input from various sources, users, and mathematical services. Communication between these different entities can be realized using OpenMath. But, such communication and the interactivity inside the mathematical document take place(More)
The problem of minimizing a polynomial function in several variables over R n is considered and an algorithm is given. When the polynomial has a minimum the algorithm returns the global minimum and nds at least one point i n e v ery connected component of the set of minimizers. A c haracterization of such points is given. When the polynomial does not have a(More)