@@ -48,7 +48,7 @@ It is recommended to use first the `Set Implicit Arguments` command to avoid wri

3. Define a relation `move : board -> board -> Prop` such that `move b1 b2` states that `b2` is obtained from `b1` by flipping over one row or one column.

4. Prove that this `move` relation is symmetric.

5. Define inductively the relation `moves : board -> board -> Prop` from the two following rules:

- Fora all `b`, we have `moves b b`

- For all `b`, we have `moves b b`

- If `moves b1 b2` and `move b2 b3` then `moves b1 b3` (for all `b1`, `b2`, `b3`).

6. Prove that the `moves` relation is reflexive, symmetric and transitive.