Es sei T = { x ∈ M ∣ f ( x ) ≥ a } {\displaystyle {}T={\left\{x\in M\mid f(x)\geq a\right\}}} . Dann ist
also
.
Dann ist
![{\displaystyle {}T\times [0,a]\subseteq S(f)\,,}](https://wikimedia.org/api/rest_v1/media/math/render/svg/a22a53749adba5da115d5621eb77e583e6de6fd2)
![{\displaystyle {}a\cdot \mu (T)=(\mu \otimes \lambda ^{1})(T\times [0,a])\leq (\mu \otimes \lambda ^{1})(S(f))=\int _{M}f\,d\mu \,.}](https://wikimedia.org/api/rest_v1/media/math/render/svg/b8a2ee361e08b662efb1a53fb95a050e352d8aa1)
