So I've been stuck on this problem for a while, trying different combinations of rules, but I can't figure it out. The problem is:
|A v B
|A v C
|A v (B n C)
The n stands for 'and', and the lines are my attempt at a Fitch line.
So I need to use subproofs within subproofs, and introduction and elimination rules for negation, conjunction, disjunction and contradiction online. I can't cite DeMorgan's laws.
I would appreciate any help. Thank you!