In this paper we discuss the existence of an optimal portfolio for every investor in a two-period Arrow-Debreu economy in which risky assets are contingent claims on aggregate consumption. Since we derive an optimal portfolio for every investor, the pricing kernel is endogenously determined. Hence the sufficient conditions for the existence of optimal portfolios given in this paper do not invol...

We report discovery of collinear-magnetism-driven ferroelectricity in the Ising chain magnet Ca3Co2-xMn(x)O6 (x approximately 0.96). Neutron diffraction shows that Co2+ and Mn4+ ions alternating along the chains exhibit an up-up-down-down ( upward arrow upward arrow downward arrow downward arrow) magnetic order. The ferroelectricity results from the inversion symmetry breaking in the upward arr...

We derive tractable necessary and sufficient conditions for the absence of buy-and-hold arbitrage opportunities in a perfectly liquid, one period market. We formulate the positivity of Arrow-Debreu prices as a generalized moment problem to show that this no arbitrage condition is equivalent to the positive semidefiniteness of matrices formed by the market price of tradeable securities and their...

836 Fig. 1. Histopathological examination revealed the colonic signet-ring cell carcinoma (arrow) (Hematoxylin-eosin staining; original magnification×200). Fig. 2A. CT showed the only hydrocele of tunica vaginalis (thin arrow) and the normal shape of testis (thick arrow) in the left scrotum during December 2010. Fig. 2B. CT showed a 6.8×4.5cm mixed density mass shadow with ill-defined margin in...