Chapter 02 / Analytic Continuation
The Topography of $|\zeta(s)|$
Euler began with a simple sum for real numbers $s > 1$: $\zeta(s) = \sum_{n=1}^\infty \frac{1}{n^s}$. Riemann extended it to the full complex plane $\mathbb{C}$. The result is an alien landscape of an infinite chimney pole, a mirror coast, and a strip of bottoms-up canyons.
The Complex Domain Map $s = \sigma + it$
Hover over features to inspect the mathematical properties of each zone.
The Singular Pole at $s = 1$
When $s = 1$, the zeta series becomes the harmonic series: $$1 + \frac{1}{2} + \frac{1}{3} + \frac{1}{4} + \cdots = \infty$$ This is the sole pole in the entire complex plane. It has residue 1. In prime distribution, this isolated pole is responsible for the overall linear expansion term $x$ in $\psi(x)$, reflecting that primes never thin out to zero.
The Trivial Zeros
Riemann’s reflection equation includes the factor $\sin(\frac{\pi s}{2})$. Whenever $s$ is a negative even integer ($-2, -4, -6, \dots$), this sine factor vanishes.
These are called the trivial zeros because their existence is an easy byproduct of elementary trigonometry. The true mystery lies strictly enclosed within the misty border $0 < \text{Re}(s) < 1$.