%0 Journal Article %T Tangent cones, starshape and convexity %A J. M. Borwein %J International Journal of Mathematics and Mathematical Sciences %D 1978 %I Hindawi Publishing Corporation %R 10.1155/s0161171278000460 %X In the last few years various infinite dimensional extensions to Krasnoselski's Theorem on starshaped sets [14] have been made. These began with a paper by Edelstein and Keener [8] and have culminated in the papers by Borwein, Edelstein and O'Brien [3] [4] by Edelstein, Keener and O'Brien [9] and finally by O'Brien [16]. %K tangent cones %K pseudo tangent cones %K starshape %K convexity %K functional conditions. %U http://dx.doi.org/10.1155/S0161171278000460