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Let's say we have n points, on which the Boltzmann distribution $P = \{p_1,p_2,...,p_n\}$ is defined. Is it generally true that $\prod_{i=1}^n p_i < \prod_{i=1}^m q_i$ if $Q = \{q_1,...,q_m \}$ is another Boltzmann distribution defined on only $m$ points among the original $n$ points with $m < n$?

The definition of Boltzmann distribution can be found, for example, via When do people actually use the maximum entropy distribution?. More precisely, $$p_i = \frac{e^{-\beta E_i}}{\sum_j e^{-\beta E_j}}$$.

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  • $\begingroup$ could you write down your definitions to make the question self contained? the link you provide contains no equations, so the definition of $P$ remains unclear. $\endgroup$ Commented Dec 24, 2021 at 15:51
  • $\begingroup$ What are the $E$'s in your definition? $\endgroup$
    – LSpice
    Commented Dec 24, 2021 at 16:26
  • $\begingroup$ Do you have a response to the answer below? $\endgroup$ Commented Dec 29, 2021 at 1:06

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The answer is yes. Indeed, by rescaling the $E_i$'s, without loss of generality (wlog) $\beta=1$. Also, by obvious induction on $m$, wlog $Q=\{p_1,\dots,p_{n-1}\}$.

Then the inequality in question becomes $$ \frac {\exp\big\{-\sum_{j=1}^n E_j\big\}}{\big(\sum_{j=1}^n e^{-E_j}\big)^n}< \frac {\exp\big\{-\sum_{j=1}^{n-1}E_j\big\}}{\big(\sum_{j=1}^{n-1}e^{-E_j}\big)^{n-1}},$$ which can be rewritten as $$e^{-E_n}\Big(\sum_{j=1}^{n-1}e^{-E_j}\Big)^{n-1}<\Big(\sum_{j=1}^n e^{-E_j}\Big)^n,$$ which is obvious, for any nonnegative values $E_j$ of energy.

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