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SIP 250, AB 42. Karp reductions – Definition. f. Karp Reductions – Ilustrated. B. F(A). A. F( *-A ). * - A. * - B. *. *. Reducing. Reductions and Efficiency. HAMPATH p HAMCYCLE. u. Check list. Closeness Under Reductions: Definition. Observation. SIP 250, AB 88.
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SIP 250, AB 42 Karp reductions –Definition
f Karp Reductions –Ilustrated B F(A) A F(*-A) * - A * - B * *
SIP 250, AB 88 Log-space Reductions
Oracle machines • An oracle Turing machine M has one extra “query tape” and three special states qquery,qyes,qno. • To execute M we specify a language O {0,1}*, that is used as the “oracle”. • When MO enters qquery, it either moves to qyes or qno according to whether the string on the query tape belongs to O or not. • An oracle call counts as one step.
Cook reduction: an example • Let L be a language • L* = { x | x=x1..xk , xi L }