Noun
(uncountable) The state of being subadditive.
The statement that a function is subadditive.
An outer measure
μ
∗
{\displaystyle \mu ^{*}}
satisfies a property called “subadditivity”, viz.:
μ
∗
(
⋃
j
=
1
∞
A
j
)
≤
∑
j
=
1
∞
μ
∗
(
A
j
)
{\displaystyle \mu ^{*}{\big (}\bigcup _{j=1}^{\infty }A_{j}{\big )}\leq \sum _{j=1}^{\infty }\mu ^{*}(A_{j})}
. If the less-than-or-equal sign were replaced with an equal sign then the property would be “additivity” instead.
Baumol also noted that for a firm producing a single product, scale economies were a sufficient but not a necessary condition to prove subadditivity. Source: Internet
This follows from the countable subadditivity of measures. Source: Internet