Prime Number Theorem And ...

2 Basic definitions and notation

Let \(p_n\) denote the \(n^{th}\) prime.

Definition 2.0.1 First prime gap
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\(P(g)\) is the first prime \(p_n\) for which the prime gap \(p_{n+1}-p_n\) is equal to \(g\), or \(0\) if no such gap exists.

Definition 2.0.2 pi
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\(\pi (x)\) is the number of primes less than or equal to \(x\).

Definition 2.0.3 li and Li
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\(\mathrm{li}(x) = \int _0^x \frac{dt}{\log t}\) (in the principal value sense) and \(\mathrm{Li}(x) = \int _2^x \frac{dt}{\log t}\).

Definition 2.0.4 Equation (2) of FKS2
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\(E_\psi (x) = |\psi (x) - x| / x\)

Definition 2.0.5 Definitions 1, 5, FKS2
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We say that \(E_\psi \) satisfies a classical bound with parameters \(A, B, C, R, x_0\) if for all \(x \geq x_0\) we have

\[ E_\psi (x) \leq A \left(\frac{\log x}{R}\right)^B \exp \left(-C \left(\frac{\log x}{R}\right)^{1/2}\right). \]

We say that it obeys a numerical bound with parameter \(\varepsilon (x_0)\) if for all \(x \geq x_0\) we have

\[ E_\psi (x) \leq \varepsilon (x_0). \]
Definition 2.0.6 Equation (1) of FKS2
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\(E_\pi (x) = |\pi (x) - \mathrm{Li}(x)| / \mathrm{Li}(x)\).

Definition 2.0.7 Equation (2) of FKS2
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\(E_\theta (x) = |\theta (x) - x| / x\)

Definition 2.0.8 Definitions 1, 5, FKS2
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We say that \(E_\theta \) satisfies a classical bound with parameters \(A, B, C, R, x_0\) if for all \(x \geq x_0\) we have

\[ E_\theta (x) \leq A \left(\frac{\log x}{R}\right)^B \exp \left(-C \left(\frac{\log x}{R}\right)^{1/2}\right). \]

We say that it obeys a numerical bound with parameter \(\varepsilon (x_0)\) if for all \(x \geq x_0\) we have

\[ E_\theta (x) \leq \varepsilon (x_0). \]
Definition 2.0.9 Definitions 1, 5, FKS2
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We say that \(E_\pi \) satisfies a classical bound with parameters \(A, B, C, R, x_0\) if for all \(x \geq x_0\) we have

\[ E_\pi (x) \leq A \left(\frac{\log x}{R}\right)^B \exp \left(-C \left(\frac{\log x}{R}\right)^{1/2}\right). \]

We say that it obeys a numerical bound with parameter \(\varepsilon (x_0)\) if for all \(x \geq x_0\) we have

\[ E_\pi (x) \leq \varepsilon (x_0). \]
Lemma 2.0.1 Admissible bound decreasing for large x
# Discussion

If \(A,B,C,R {\gt} 0\) then the classical bound is monotone decreasing for \(x \geq \exp ( R (2B/C)^2 )\).

Proof

Differentiate the bound and check the sign.

A classical bound for \(x \geq x_0\) implies a numerical bound for \(x \geq \max (x_0, \exp ( R (2B/C)^2 ))\).

Proof

Immediate from previous lemma