http://hdl.handle.net/123456789/2134 البحث عن قناة بحث http://repository.ksu.edu.sa/jspui/simple-search http://hdl.handle.net/123456789/6715 العنوان: The numerical range of linear operators<br/><br/>المؤلفون: Mecheri, Salah<br/><br/>ملخص: In [27] J.P.Williams showed that an operator A E B(H) is normaloid if and only if it is convexoid. It is known thatthe part if in J.P.William’s result is not true as it mentioned inthe review MR0264445. In this paper we will present an examplewhich contractics the part “ if ” in J.P. williams’ result. We alsogive a simple proof of the part “only if” of this result. A necessary and sufficient condition for an operator A E B(H) to be convexoid is also given.<br/><br/>وصف: Department of mathematicsKing saud university, college of scienceP.o.box 2455, Riyadh 11451, Saudi arabia Tue, 01 Jan 1991 00:00:00 GMT http://hdl.handle.net/123456789/4890 العنوان: Decomposition method for one dimensional biharmonic equations<br/><br/>المؤلفون: Khalifa, A.K.<br/><br/>ملخص: This paper deals with the study of the numerical solution of biharmonic equations inone dimension. Biharmonic equations appear frequently in many areas of engineering andphysics representing some phenomena. The solution of such problems have been tackled bymany authors. In this paper, a numerical method based on the Adomian decomposition method isintroduced for the approximate solution of the equations. The obtained results are presentedwhere only a few terms are required to obtain a good approximation to the solution. This showsthat the method is accurate and efficient. Sun, 01 Jan 2006 00:00:00 GMT http://hdl.handle.net/123456789/2399 العنوان: A coincidence theorem for symmetric multilinear forms<br/><br/>المؤلفون: Jamjoom, Fatma B.; Zaheer, Neyamat<br/><br/>ملخص: We obtain a coincidence theorem for (vector-valued) symmetric multilinearforms which generalizes an important classical result due to 1. L. Walsh, commonlyknown as "Walsh's coincidence theorem" on symmetric n-linear forms in complexvariables. Our main theorem, being a storehouse of many applications (as isWalsh's theorem in the classical theory), provides new results as well as a largenumber of known results due to Walsh, Zervos, Marden, Hormander, Szego, andZaheer (some in improved forms). We also give a number of examples in support ofcertain claims that we make about our main theorem<br/><br/>وصف: Department of Mathematics, King Saud University Fri, 01 Jan 1988 00:00:00 GMT