Question1:
argument: I will be at the park tonight, unless my van breaks down. If April is at the park, then either Abby or Brian will be there, too. But, if Abby will be at the park, then April won’t be, and if my car breaks down, then Brian won’t be, either. So, if Brian will be at park tonight, then so will I.
Construct a symbolization key to translate the argument. Then, provide a proof of its validity in the proof system.