Z = e − ψ = ∑ i e − λ ν M i ν {\displaystyle Z={{e}^{-\psi }}=\sum \limits _{i}{{e}^{-{{\lambda }_{\nu }}M_{i}^{\nu }}}}
∑ i P i = 1 {\displaystyle \sum \limits _{i}{{P}_{i}}=1}
