WordNet sense 1 (the result of improving something):

refinement

WordNet sense 2 (a discussion that provides additional information):

enlargement, expansion

WordNet sense 3 (marked by elaborately complex detail):

elaborateness, intricacy, involution

WordNet sense 4 (addition of extra material or illustration or clarifying detail):

amplification

WordNet sense 5 (developing in intricate and painstaking detail):

working out