Theorem stoic1b

Stoic logic Thema 1 (part b). The other part of thema 1 of Stoic logic; see stoic1a. (Contributed by David A. Wheeler, 16-Feb-2019.)

Hypothesis
stoic1.1
\( \vdash \varphi \wedge \psi \rightarrow \theta \)
Conclusion
\( \vdash \psi \wedge \neg \theta \rightarrow \neg \varphi \)
Proof
stoic1.1
ancoms _
stoic1a _