proving {$a^ib^jc^k : j = i \lor j = k$} is not regular i had troubles proving this  is not regular using the pumping lemma {$a^ib^jc^k : j = i \lor j = k$}. Not sure how to approach this anymore, and help would be appreciated
If you intersect your language with $a^+ b^+$ then you get $\{ a^n b^n : n \ge 1 \}$, whose irregularity you probably know how to prove.