theorem

Theorem 19.3

Bounded access characterizes regularity

Theorem 19.3 (Bounded access characterizes regularity). For a language LL, the following are equivalent: L is regular⟺sup⁡NaL(N)<∞⟺aL(N) is eventually constant.L\text{ is regular} \quad\Longleftrightarrow\quad \sup_N a_L(N)<\infty \quad\Longleftrightarrow\quad a_L(N)\text{ is eventually constant}.