Chapter 7.1 - 7.4

Logical Agents

The emphasis of this chapter is on knowledge representation such as propositional logic (aka propositional calculus) and first order logic (aka predicate calculus). In order to use a knowledge representation, reasoning (aka search) is needed and learning might be needed.

7.1 Knowledge-Based Agents

• Knowledge Base (Declarative vs. Procedural)
• Tell query
• Ask query

7.2 Wumpus World

7.3 Logic Terminology

• Syntax
• Semantics: defines the truth of each sentence with respect to each possible world (or model).
• Entailment: sentence A |= sentence B
• Inference: KB |- sentence A
• Sound: An inference algorithm only derives entailed sentences
• Complete: An inference algorithm can derive any entailed sentence

7.4 Propositional Logic

Syntax

• Constants: True, False
• Propositional Symbols: P, Q, etc.
• Logical Connectives: and, or, not, implication, biconditional
• Figure 7.7: BNF Grammar

Semantics

Truth tables for each of the logical connectives.

Logical Equivalency

See Figure 7.11.

Satisfiability

NPC!