we define a new type of spectrum, called δ-approximate spectrum, of an element a in a complex unital banach algebra a and show that the δ-approximate spectrum σ_δ (a) of a is compact. the relation between the δ-approximate spectrum and the usual spectrum is investigated. also an analogue of the classical gleason-kahane-zelazko theorem is established: for each ε>0, there is δ>0 such that if ϕ is...

A variation of the Almost Ideal Demand System (AIDS) model of Deaton and Muellbauer (1980) has been employed to determine the impacts of per capita total expenditure, food prices and demographic variables on household demand for dairy products in Bangladesh. The budget shares are generally more responsive to per capita total expenditure than to prices. With respect to demographic effects, it is...

Through this paper, we have attempted to model the demand for di¤erent classes of antibiotics used for respiratory infections in outpatient care in Switzerland using a spatial version of the linear approximate Almost Ideal Demand System (AIDS) model. This model takes spatial dependency into account by means of spatial lags of antibiotic budget shares. We control for the health status of patient...

The linear approximate version of the almost ideal demand system (LA-AIDS) model is estimated using data from the Lithuanian household budget survey (HBS) covering the period from July 1992 to December 1994. Price and real expenditure elasticities for 12 food groups were estimated based on the estimated coefficients of the model. Very little or nothing is known about the demand parameters of Li...

Abstract Export promotion at the extensive margin is a key concern of governments. We develop measures how far firms in origin sectors are from break-even entry destination markets. The measure based on Almost Ideal gravity featuring heterogeneous price and income elasticities. Tobit estimation 2006 trade flows for 75 countries 25 generates Latent Trade Bias (LTB) – latent (projected) share non...

We show that certain matrix approximation problems in the matrix 2-norm have uniquely defined solutions, despite the lack of strict convexity of the matrix 2-norm. The problems we consider are generalizations of the ideal Arnoldi and ideal GMRES approximation problems introduced by Greenbaum and Trefethen [SIAM J. Sci. Comput., 15 (1994), pp. 359–368]. We also discuss general characterizations ...