Difference between revisions of "Prime counting"

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File:Primecountingfunction.png|Plot of $\pi(x)$ over $[0,50]$.
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File:Primecountingplot.png|Graph of $\pi(x)$.
File:Primecountingfunctiondividedbyxoverlogx.png|Plot of $\frac{\pi(x)}{x/\log(x)}$ on $[0,1000000]$.
 
 
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Revision as of 20:03, 16 May 2016

The prime counting function $\pi \colon \mathbb{R} \rightarrow \mathbb{Z}^+$ is defined by the formula $$\pi(x) = \{\mathrm{number \hspace{2pt} of \hspace{2pt} primes} \leq x \}.$$

Properties

Theorem

The function $\pi(x)$ obeys the formula $$\lim_{x \rightarrow \infty} \dfrac{\pi(x)}{\frac{x}{\log(x)}}=1,$$ where $\pi$ denotes the prime counting function and $\log$ denotes the logarithm.

Proof

References

Theorem

The following formula holds: $$\lim_{x \rightarrow \infty} \dfrac{\pi(x)}{\mathrm{li}(x)}=1,$$ where $\pi$ denotes the prime counting function and $\mathrm{li}$ denotes the logarithmic integral.

Proof

References

References

Newman's short proof of the prime number theorem