# Logical agents

## Inference Algorithms

they have these properties:

- Sounding or Truth-preserving: finds only real entailed sentences
- Completeness: Same as Searching in Ch 3
- Grounding: How can be sure that our knowledge is real

## Sentences

They have the following properties:

- logical equivalence: These sentences are logically the same
- Validity: A sentence is valid if equivalent to true sentence (True in all worlds)
- Satisfiability: True in **some** worlds