Let L5 be the language { {G,D} | G is a CFG, D is a DFA, and L(D) ⊆ L(G) }
Show that L5 is undecidable. Is L5 R.E.? Is it co-R.E.?
I am not quite sure where exactly to start with this. Could someone help me in proving L5 is undecidable
2026-03-26 18:30:15.1774549815
Proving languages are undecidable
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This was first published by Hopcroft in 1969. See the elegant proof here.