Fixed partition index typo.

src/fa/rs/partition.tex

@@ -30,7 +30,7 @@
 
 \begin{definition}[Fine]
 \label{definition:partition-refinement}
-    Let $P = \seqfz[m]{x_j}, Q = \seqfz{y_j} \in \scp([a, b])$, then $Q$ is \textbf{finer} than $P$ if for every $0 \le j \le m$, there exists $0 \le k \le m$ such that $x_j = y_k$. For any $P, Q \in \scp([a, b])$, denote $P \le Q$ if $Q$ is finer than $P$, then
+    Let $P = \seqfz[m]{x_j}, Q = \seqfz{y_j} \in \scp([a, b])$, then $Q$ is \textbf{finer} than $P$ if for every $0 \le j \le m$, there exists $0 \le k \le n$ such that $x_j = y_k$. For any $P, Q \in \scp([a, b])$, denote $P \le Q$ if $Q$ is finer than $P$, then
     \begin{enumerate}
         \item $\scp([a, b])$/$\scp_t([a, b])$ equipped with $\le$ is a upward-directed set.
         \item If $P \le Q$, then $\sigma(P) \ge \sigma(Q)$.