| Language | Type |
|---|---|
| EQ = {<G1, G2> | G1, G2 are CFGs and L(G1) = L(G2)} |
| ALL = {<G> | G is a CFG and L(G) = Σ∗} |
| ETM = {< M > | M is a TM and L(M) = ∅} |
| A = {a^ib^ic^j | i ≠ j} |
| A = {a^ib^ic^i | i≥ 0} |
| {0^n1^n | n > 1} |
| {0^n1^n2^n | n > 1} |
| 0^m1^n2^n | m,n > 1} |
| 0^k1^m2^n | k,m,n > 1} |
This type of language, where there is a need to count and match multiple different types of symbols in a specific order, typically exceeds the capabilities of a context-free grammar.