http://dswarmsikhttkg7jgsoyfiqpj3ighupfrvuz5ri3lu5q2dlqyrpgk7ad.onion/notes/lsg.html
It is raining. Therefore , Jane has her umbrella with her. If \(p\) and not \(q\) , then \(r\) .
Not \(r\). \(p\).
Therefore, \(q\). The sequent * for Examples 1.1 and 1.2: \(p \land \neg q \to r, \neg r, p \vdash q\) Example 1.4 Prove that \(p \land q, r \vdash q \land r\) is valid.