## How do you solve Fitch proofs?

The above solutions were **written up in the Fitch proof editor**.

Examples of Fitch Proofs:

1. | Prove q from the premises: p ∨ q, and ¬p. | Solution |
---|---|---|

2. | Prove p ∧ q from the premise ¬(¬p ∨ ¬q) | Solution |

3. | Prove ¬p ∨ ¬q from the premise ¬(p ∧ q) | Solution |

4. | Prove a ∧ d from the premises: a ∨ b, c ∨ d, and ¬b ∧ ¬c | Solution |

## What is a Fitch proof?

Fitch-style proofs **arrange the sequence of sentences that make up the proof into rows**. A unique feature of Fitch notation is that the degree of indentation of each row conveys which assumptions are active for that step.

## How do you use Fitch?

Quote:

*You can also as we've mentioned before create shortcuts the Fitch program is represented by the F icon with the backwards e. And variable X and the letter capital letter P.*

## How do you prove a case?

The idea in proof by cases is to **break a proof down into two or more cases and to prove that the claim holds in every case**. In each case, you add the condition associated with that case to the fact bank for that case only.

## What is natural deduction in artificial intelligence?

In natural deduction, **to prove an implication of the form P ⇒ Q, we assume P, then reason under that assumption to try to derive Q**. If we are successful, then we can conclude that P ⇒ Q. In a proof, we are always allowed to introduce a new assumption P, then reason under that assumption.