IAS/PCMI Summer Session 2000 Clay Mathematics Undergraduate Program Basic Course on Computational Complexity Lecture 2: The Complexity of Some Problems
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چکیده
We first present a machine that decides parity. The machine scans the input from left to right. After looking at each bit, the machine remembers whether the number of 1’s seen so far is odd or even. Initially, the number is 0 and therefore even. The machine then toggles between even and odd for each 1 seen in the input, and does nothing for each 0. This even/odd toggle can be incorporated into the internal states of the machine or it can be stored explicitly in its memory. In either case, the machine uses a constant amount of space and parity is in DSPACE(1).
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IAS/PCMI Summer Session 2000 Clay Mathematics Undergraduate Program Basic Course on Computational Complexity Lecture 5: The Landscape of Complexity Classes
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