This is a document I wrote with a really cool strategy to solve derivations in Predicate Logic. It assumes you already know how to apply rules from Propositional Logic and are familiar with the new rules from Predicate Logic and Identity.
I've done this because natural deduction is a really nice thing. It's actually fun to build the derivation trees. Also, I wanted to document what I've learned because I've seen many people having trouble with natural deduction in predicate logic, even if they understood the topic correctly in propositional logic.
I think the main problem is that it's hard to get lost into the construction if you are not organized. For this I show two examples, first one shows a general strategy to build any derivation in predicate logic. Second one show's the application of the identity rules, specially the 4th which is usually the hardest to understand if you don't specify everything really clear.
- Here's the original latex file of the document (which was originally written in spanish). So if you find an error or any kind please submit your corrections.
- Also you will find the latest PDF file generated from the latex file.