A signed measure on the measurable space $(X,\Sigma)$ is a function \(\mu: \Sigma \to \mathbb R \cup \{-\infty\} \text{ or } \mathbb R \cup \{\infty\}\) such that $\mu(\emptyset) =0$ and $\mu$ is σ-additive. Note that $\mu$ cannot take on both $-\infty$ and $\infty$ as values.
Wikidata ID: Q1764371