+/**
+ * Check whether this vector's thread has synchronized with another action's
+ * thread. This effectively checks the happens-before relation (or actually,
+ * happens after), but it's easier to compare two ModelAction events directly,
+ * using ModelAction::happens_before.
+ *
+ * @see ModelAction::happens_before
+ *
+ * @return true if this ClockVector's thread has synchronized with act's
+ * thread, false otherwise. That is, this function returns:
+ * <BR><CODE>act <= cv[act->tid]</CODE>
+ */
+bool ClockVector::synchronized_since(const ModelAction *act) const