week2 - Week 2: Lecture 3 TM : tape: two way, can write...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Week 2: Lecture 3 TM : tape: two way, can write Formally, Turing machine M is a 7-tuple, (Q, , , , q0, q accept , q reject ,), where 1. Q is the set of states 2. is the input alphabet not containing the special blank symbol 3. is the tape alphabet, where { } and 4. : Q Q {L.R} is the transition function (not a mapping) 5. q0 Q is the initial state 6. q accept Q is the accept state 7. q reject Q is the reject state, where qaccept, qreject Configuration of M: uqv (head is at the first symbol of string v) Start configuration Accepting configuration uaq i bv yields uacq j v if (q i ,b) = (q j ,c,R) M accepts w: C1 is the start conf of M on input w Each C i yields C i+1 C k is the accepting conf Note that the definition hold even for a NDTM. Even in this case, we have many variations: determinism vs. non det 1 tape vs. multi tape read only vs. read write Theorem: If an algorithm A has time complexity O(n k ), then there is a TM M which can implement A in O(n...
View Full Document

Page1 / 4

week2 - Week 2: Lecture 3 TM : tape: two way, can write...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online