[PATCH] memorder: Reconcile Figure 15.15 notation with W+RWC z-flow semantics

State explicitly that Figure 15.15 uses x as a schematic variable name, while the surrounding W+RWC analysis in Listing 15.18 follows the concrete z-flow (P2 -> z -> P1). This eliminates notation drift across cross-references and preserves propagation-argument fidelity.

Signed-off-by: Kunwu Chan <[email protected]>
---
 memorder/memorder.tex | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/memorder/memorder.tex b/memorder/memorder.tex
index 2357e7ea..8eb14a29 100644
--- a/memorder/memorder.tex
+++ b/memorder/memorder.tex
@@ -2760,6 +2760,8 @@ that \co{P1()}'s read from \co{z} happens much later in time, but
 nevertheless still sees the old value of zero.
 This situation is depicted in
 \cref{fig:memorder:Load-to-Store is Counter-Temporal}:
+The figure uses \co{x} as a generic variable name for the same
+counter-temporal pattern.
 Just because a load sees the old value does \emph{not} mean that
 this load executed at an earlier time than did the store of the
 new value.
-- 
2.25.1