Corollary 3.15.
A map \(*\to X\) in a topos \(T\) is an effective epimorphism if and only if \(\tau_0 X\) is the terminal object of \(T\).
Higher Topos Theory Section 3.1: Truncation
Corollary 3.15.
A map \(*\to X\) in a topos \(T\) is an effective epimorphism if and only if \(\tau_0 X\) is the terminal object of \(T\).