restriction on the number of measurable sets with finite measure. Every -finite measure is a decomposable measure, the converse is not true. s-finite measures A measure is called a s-finite measure if it is the sum of at most countably many finite measures. Every σ-finite measure is s-finite, the converse is not true. For a proof and counterexample see s-finite measure#Relation to σ-finite measures. See also Sigma additivity References Measures (measure theory)