Show that for any nfa for all $q ∈Q$ and all $w, v ∈ Σ^*$ :
$\delta ^*(q,wv)=\cup _{p\epsilon \delta ^*(q,w)}\delta ^*(p,v)$
[Use Definition: For an nfa, the extended transition function is defined so that $δ^* (q_i,w)$ contains $q_j$ if and only if there
is a walk in the transition graph from $q_i$ to $q_j$ labeled $w$. This holds for all $q_i, q_j ∈ Q$, and $w ∈ Σ^*$.]
