FAQ Database Discussion Community

## How does 'elim' in Coq work on existential quantifier?

coq,first-order-logic
I'm confused by Coq on its way dealing with existential quantification. I have a predicate P and an assumption H P : nat -> Prop H : exists n, P n while the current goal is (whatever) (Some goal) If I want to instantiate n in H, I will do...

## Recreating the if/else in groovy: giving multiple closures arguments to a function

groovy,closures,first-order-logic
While trying to reinvent the if/else syntax with closures in groovy, I couldn't manage to make it work. I think putting multiple closures outside the parenthesis is not permitted, but it could be something else. If it isn't permitted, how would you reproduce the if/else syntax? This is a thought...

## Describe a film (entity and attribute) using the first order logic

logic,semantics,semantic-web,first-order-logic
Good morning, I want to understand how can I describe something using the first order logic. For example I want to describe what is a film (an entity) and what is an attribute (for example actor: Clooney) for the film. How can I describe that using the first order logic?...

## Fixed Point and Proof theory

logic,proof,logic-programming,first-order-logic
For any given logic program, proof theory of it uses SLD (Selective Linear Definite) resolution to find the satisfiablity of the query. For the same logic program, we can apply fixed point theorem to find the models. My question is, should we consider finding fixed point of logic programs as...