I am trying to make sense of a Russian author’s use of terms (I have to translate his article). I have three questions, but please don't think you need to answer all three before answering. Thanks for any insights!  He uses the term “probability density distribution” ρ(ξ) of a stationary (stochastic) process ξ.This sounds to me like a hybrid of “probability distribution” and “probability density function”, and that only one of them should be chosen. Am I wrong? If so, the first one?  when talking about stationary processes, he writes in the original “stationary stochastic process”. Is this redundant –shall I eliminate “stochastic”, or leave it in?  When he is referring to deBroglie waves, he writes “deBroglie matter waves”. Is the “matter” definitely to be left out, or can it be left in for emphasis?