Which of the following languages is/are not regular if L is the regular language over ∑(a, b)?
1
L1: {\(wxw^R| w, x \varepsilon\text{ {a, b}*}\) and |w|, |x| > 0}, \(w^R\) is the reverse of string w
2
L2 {wwR | w ϵ L}
3
L3: { ap bq c2p ) | p, q ≥ 1}
4
Suffix (L4) = {y ϵ ∑* | ∃x ϵ ∑* such that xy ϵ L4}