CS 2401 - Introduction to Complexity Theory Lecture # 5 : Fall , 2015
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چکیده
• Previously covered L, NL, PSPACE, NPSPACE – A language L is in SPACE(s(n)), where s : N → N, iff there is a deterministic TM M deciding L such that, on any input of length n, M ’s tape head visits at most c · s(n) cells over all non-input tapes, where c is a constant – Similarly, L ∈ NSPACE(s(n)) iff there is a non-deterministic TM M deciding L such that, on any input of length n and for any possible sequence of configurations, M ’s tape head visits at most c · s(n) cells over all non-input tapes – Saw that L ⊆ NL ⊆ P ⊆ PSPACE ⊆ NPSPACE • Introduced TQBF, the problem of determining the truth of quantified boolean formulas, i.e. boolean formulas of the form
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