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sav08:remarks_on_ws1s_complexity [2010/11/23 19:22] hossein |
sav08:remarks_on_ws1s_complexity [2010/11/23 19:29] hossein |
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====== Remarks on WS1S Complexity ====== | ====== Remarks on WS1S Complexity ====== | ||
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===== Complexity of One Algorithm ===== | ===== Complexity of One Algorithm ===== | ||
- | The construction in [[Using Automata to Decide WS1S]] determinizes automaton whenever it needs to perform negation. Moreover, existential quantifier forces the automaton to be non-deterministic. Therefore, with every alternation between $\exists$ and $\forall$ we obtain an exponential blowup. For formula with n alternations we have $2^{2^{\ldots 2}}$ complexity with a stack of exponentials of height $n$. Is there a better algorithm? | + | The construction in [[Using Automata to Decide WS1S]] determinizes automaton whenever it needs to perform negation. Moreover, existential quantifier forces the automaton to be non-deterministic. Therefore, with every alternation between $\exists$ and $\forall$ we obtain an exponential blowup. For formula with n alternations we have $2^{2^{\ldots 2^{n}}}$ complexity with a stack of exponentials of height $n$. Is there a better algorithm? |
===== Reference ===== | ===== Reference ===== | ||
- | A. R. Meyer: [[http://publications.csail.mit.edu/lcs/pubs/pdf/MIT-LCS-TM-038.pdf|Weak monadic second order theory of successor is not elementary recursive]], Preliminary Report, 1973. | + | A. R. Meyer: [[http://publications.csail.mit.edu/lcs/specpub.php?id=37|Weak monadic second order theory of successor is not elementary recursive]], Preliminary Report, 1973. |
===== Lower Bound ===== | ===== Lower Bound ===== |