Abstract Truth predicates are widely believed to be capable of serving a certain logical or quasi-logical function. There is little consensus, however, on the exact nature this We offer series formal results in support thesis that disquotational truth device simulate higher-order resources first-order setting. More specifically, we show any theory formulated language can naturally and conservat...

Tractable subsets of first-order logic are a central topic in AI research. Several these formalisms have been used as the basis for probabilistic languages. However, intractable, losing original motivation. Here we propose first non-trivially tractable language. It is subset Markov logic, and uses class part hierarchies to control complexity. We call it TML (Tractable Logic). show that knowledg...