L = { w : w ∈ {a, b}* ∧ (u, v, z ∈ {a, b}*) (|u| = 2 ∧ |z| = 2 ∧ w = uvz ∧ u ≠ z)}
Can someone explain me this language? What is w = uvz supposed to mean?
I thought I understood correctly, so the words from this language could be for example: ε, aaab, aaba, bbaa, bbba...