1. In 1922 Behmann proved that the monadic predicate calculus is decidable. 2. The validities of monadic predicate calculus with identity are decidable, however. 3. The underlying logic is classical propositional calculus and classical predicate calculus with equality. 4. In 1922 proofed that Monadic predicate calculus is decidable. 5. We work with first-order predicate calculus . 6. We fix some axiomatization of the predicate calculus : logical axioms and rules of inference. 7. This more narrow definition is often applied in predicates in the tradition of predicate calculus . 8. In a predicate calculus , relevance requires sharing of variables and constants between premises and conclusion. 9. Definitions in KL-ONE can be directly mapped to set theory and the predicate calculus . 10. It is so weak that, unlike the full predicate calculus , it is domains ).