Use Sider's semantic validity proof method to prove valid in system K the following modal wffs: 1. (O(A) B) & CA) > OB 2
Posted: Fri Apr 29, 2022 12:04 pm
Use Sider's semantic validity proof method to prove valid in system K the following modal wffs: 1. (O(A) B) & CA) > OB 2. O(A) B) ) (OA) DB) 3. DO (A&B) > ODA