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Prime Numbers

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10 Chapter 1 PRIMES!<br />

naive subroutines, has bit complexity O(ln 3 z) for positive integer operands<br />

x, y, z of comparable size, and so is polynomial-time. Similarly, taking a<br />

greatest common divisor (gcd) is polynomial-time, and so on.<br />

1.1.5 How primes are distributed<br />

In 1737, L. Euler achieved a new proof that there are infinitely many primes:<br />

He showed that the sum of the reciprocals of the primes is a divergent sum,<br />

and so must contain infinitely many terms (see Exercise 1.20).<br />

In the mid-19th century, P. Chebyshev proved the following theorem, thus<br />

establishing the true order of magnitude for the prime-counting function.<br />

Theorem 1.1.3 (Chebyshev). There are positive numbers A, B such that<br />

for all x ≥ 3,<br />

Ax<br />

Bx<br />

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