Correspondence: zuozhanfei@139. com Department of Mathematics and Statistics, Chongqing Three Gorges University, Wanzhou 404000, China Abstract We determine and estimate the Ptolemy constant of absolute normalized norms on R by means of their corresponding continuous convex functions on [0, 1]. Moreover, the exact values were calculated in some concrete Banach spaces. 2000 Mathematics Subject C...

physical explanation of the planets’ place in the heaven is one of the principal questions in the ancient astronomy which the authors of hay?a (cosmology) works tried to find an answer for it. their opinion is in fact a compilation from aristotle’s “fifth element” theory and ptolemy’s “prisms” theory. aristotle’s fifth element theory assumes that the substance of the heavens is different from t...