This paper describes an Irish ISP’s attempts to combat the abuse of resources caused by unsolicited commercial email. We describe the extension of a multicast system, used to implement POP-before-SMTP relaying, to share information about remote mail servers between multiple mail systems. The information may then be used to tarpit abusive servers – placing delays between SMTP protocol answers th...

Since the pioneering work by Kripke and Montague, the term possible world has appeared in most theories of formal semantics for modal logics, natural languages, and knowledge-based systems. Yet that term obscures many questions about the relationships between the real world, various models of the world, and descriptions of those models in either formal languages or natural languages. Each step ...

Natural languages have words for all the operators of first-order logic, modal logic, and many logics that have yet to be invented. They also have words and phrases for everything that anyone has ever discovered, assumed, or imagined. Aristotle invented formal logic as a tool (organon) for analyzing and reasoning about the ontologies implicit in language. Yet some linguists and logicians took a...