The implication operation on partitions

Partitions and equivalence relations In a 2001 commemorative volume for my mathematical mentor, Gian-Carlo Rota, three of his associates noted that “the only operations on the family of equivalence relations fully studied, understood and deployed are the binary join and meet operations.” This note defines the apparently new operation of implication for partitions, an operation […]

From propositional logic to subset logic to partition logic

From propositional logic to subset logic This note outlines the following sequence of ideas. First, ordinary propositional logic is reinterpreted as the logic of subsets of a universe set U, with the propositional case being isomorphic to the special case of U = 1. Then the category-theoretic duality between subsets of a set and partitions […]

Straight-line and Hoskold Capitalization in Real Estate Appraisal

Here is the paper you have been waiting for: Ellerman, David. 1994. “New Results on the Straight Line & Hoskold Methods of Capitalization.” Real Property Perspectives, no. July: 29–36, 80–81.