In this paper, we consider the problem of spherical distribution of 5 points, that is, how to configure 5 points on the unit sphere such that the mutual distance sum is maximal. It is conjectured that the sum of distances is maximal if the 5 points form a bipyramid distribution with two points positioned at opposite poles of the sphere and the other three positioned uniformly on the equator. We study this problem using interval methods and related techniques, and give a computer-assisted proof.

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This paper provides a new, geometric perspective to study successive difference substitutions, and proves that the sequence of the successive difference substitution sets is not convergent. An interesting result that a given k-dimensional rational hyperplane can be transformed to a k-dimensional coordinate hyperplane of new variables by finite steps of successive difference substitutions is presented. Moreover, a sufficient condition for the sequence of the successive difference substitution sets of a form being not terminating is obtained. That is, a class of polynomials which cannot be proved to be positive semi-definite by the successive difference substitution method are obtained.

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