Windable Heads Recognizing NL with Constant Randomness

12/03/2019
by   M. Utkan Gezer, et al.
0

Every language in NL has a k-head two-way nondeterministic finite automaton (2nfa(k)) recognizing it. It is known how to build a constant-space verifier algorithm from a 2nfa(k) for the same language with constant-randomness, but with error probability k^2-12k^2 that can not be reduced further by repetition. We have defined the unpleasant characteristic of the heads that causes the high error as the property of being "windable". With a tweak on the previous verification algorithm, the error is improved to k_W^2-12k_W^2, where k_W< k is the number of windable heads. Using this new algorithm, a subset of languages in NL that have a 2nfa(k) recognizer with k_W< 1 can be verified with arbitrarily reducible error using constant space and randomness.

READ FULL TEXT

Please sign up or login with your details

Forgot password? Click here to reset

Sign in with Google

×

Use your Google Account to sign in to DeepAI

×

Consider DeepAI Pro