This chapter is all about understanding the various terms used in AI

Some Basics

→ Logics are formal languages for representing information such that conclusions can be drawn

→ Sentence is a piece of information.

• Satisfiable if it is true under some interpretations
• Valid if it is true under all possible interpretations
• Inconsistent if there does not exist any interpretation under which the sentence is true

→ Syntax defines the sentences in the language.

→ Semantics define the meaning of sentences.

Example: x+2 ≥ y is a sentence; x2+y > {} is not a sentence

→ Entailment means that one thing follows from another: K

$$ KB |=\alpha $$

• Knowledge base KB entails the sentence α if and only if α is true in all worlds where KB is true.

→ Ontology is the study of what there is - an inventory of what exists. An ontological commitment is a commitment to an exciting claim. What exists in the world

→ Epistemology is a major branch of philosophy that concerns the forms, nature, and preconditions of knowledge. What an agent believes about facts

→ Axioms are facts and rules that attempt to capture all of the (important) facts and concepts about a domain. axioms can be used to prove theorems.

What is a Knowledge-based Agent

A knowledge-based agent includes a knowledge base and an inference system. It is a set of representations of facts of the world. Where each individual representation is called a sentence. The sentences are expressed in a knowledge representation language.

The agents operate as follows:

1. tells the KB what it perceives.
2. asks the KB what action it should perform
3. performs the chosen action.

Logic

Logic is a powerful and well-developed approach to drawing reasonable conclusions from a set of data that can be programmed to use and generate solutions.