Editing Algorithmic probability (section)

=== II. Levin's Universal Distribution ===

Given that any uniquely-decodable code satisfies the Kraft-McMillan inequality, prefix-free Kolmogorov Complexity allows us to derive the Universal 
Distribution:

:<math>
P(x) = \sum_{U(p) = x} P(U(p) = x) = \sum_{U(p) = x} 2^{-K_U(p)} \leq 1 </math>

where the fact that <math>U</math> may simulate a prefix-free UTM implies that for two distinct descriptions <math>p</math> and <math>p'</math>, <math>p</math> isn't 
a substring of <math>p'</math> and <math>p'</math> isn't a substring of <math>p</math>.