How to learn resolution in predicate logic?

[shivajikobardan]

This is not really a homework question so don't bother answering them. It is more of a guidance problem. This is what I find the hardest out of all topics.. Unfortunately, this topic is a fixed 10 marks question in our 80 marks exam. Comes every time.

 

The types of questions that I need to deal with my exams are like this-:

john likes all kinds of food.

apples are food

chicken is food

anything anyone eats and isn't killed by is food

bill eats peanuts and is still alive.

sue eats everything bill eats.

prove that john like peanuts using resolution.

[Ghideon]

3 hours ago, shivajikobardan said:

This is not really a homework question so don't bother answering them. It is more of a guidance problem.

Some general notes how I may approach these kind of problems. Disclaimer: This is a quick outline of my personal approach, your mileage may vary.

- My first language is not English; check if I understand what is written. Otherwise clarify first.

- Is there an "obvious" solution? If so, keep that solution for verification/falsification later.

- Are the statements constructed to "trick" the reader? (Example: "All apples are blue" is false in reality but an ok premise in an example. "isn't killed by" is probably not a common way to define food (?) )

- Is there a resolution that "should" be true. (Example "Apple is a fruit" is likely true in a well constructed problem. "Apples are not fruits" is less likely. (Double) check solutions that does not make sense in real life)

- Is there extra information not needed?

Then move on to translate the sentences into logic statements and apply rules.

Side note: in the example given I would add that although John likes peanuts we can not say for sure that he will survive without proper treatment; we can't decide whether he is allergic or not. In real life (in my day job for instance) spotting these kind of things may be just as important as the question stated. 

Edited February 14, 2022 by Ghideon
grammar