Arjun Suresh (talk | contribs) (→For CFGs G, G1 and G2 and regular set R) |
Arjun Suresh (talk | contribs) (→For CFGs G, G1 and G2 and regular set R) |
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The following problems are undecidable: | The following problems are undecidable: | ||
− | # <math>(L(G1))^\complement</math> is a CFL | + | # Whether <math>(L(G1))^\complement</math> is a CFL |
− | # L(G1) \cap L(G2) is a CFL | + | # Whether <math>L(G1) \cap L(G2)</math> is a CFL |
− | # L(G1) \cap L(G2) is empty | + | # Whether <math>L(G1) \cap L(G2)</math> is empty |
− | # L(G1) = R | + | # Whether <math>L(G1) = R</math> |
− | # Whether G is ambiguous | + | # Whether <math>G</math> is ambiguous |
Grammar | <math>w \in L(G)</math> | <math>L(G) = \phi</math> | <math>L(G) = \Sigma^*</math> | <math>L(G_1) \subseteq L(G_2)</math> | <math>L(G_1) = L(G_2)</math> | <math>L(G_1) \cap L(G_2) = \phi</math> | <math>L(G) is finite</math> |
---|---|---|---|---|---|---|---|
Regular Grammar | D | D | D | D | D | D | D |
Det. Context Free | D | D | D | UD | ? | UD | D |
Context Free | D | D | UD | UD | UD | UD | D |
Context Sensitive | D | UD | UD | UD | UD | UD | UD |
Recursive | D | UD | UD | UD | UD | UD | UD |
Recursively Enumerable | D | UD | UD | UD | UD | UD | UD |
The following problems are undecidable:
Grammar | <math>w \in L(G)</math> | <math>L(G) = \phi</math> | <math>L(G) = \Sigma^*</math> | <math>L(G_1) \subseteq L(G_2)</math> | <math>L(G_1) = L(G_2)</math> | <math>L(G_1) \cap L(G_2) = \phi</math> | <math>L(G) is finite</math> |
---|---|---|---|---|---|---|---|
Regular Grammar | D | D | D | D | D | D | D |
Det. Context Free | D | D | D | UD | ? | UD | D |
Context Free | D | D | UD | UD | UD | UD | D |
Context Sensitive | D | UD | UD | UD | UD | UD | UD |
Recursive | D | UD | UD | UD | UD | UD | UD |
Recursively Enumerable | D | UD | UD | UD | UD | UD | UD |
The following problems are undecidable: