Index: doc/theses/jiada_liang_MMath/CFAenum.tex
===================================================================
--- doc/theses/jiada_liang_MMath/CFAenum.tex	(revision 59fb46243b69fa66cdb75d1fddc0fbaaaf7e0bf1)
+++ doc/theses/jiada_liang_MMath/CFAenum.tex	(revision f3abce961730a076add7c8efe035e28682936f37)
@@ -204,8 +204,16 @@
 enum( char ) Letter { A = 'A', ... };
 enum( @Letter@ ) Greek { Alph = A, Beta = B, ... }; // alphabet intersection
-\end{cfa}
-Enumeration @Greek@ may have more or less enums than @Letter@, but the enum values \emph{must} be from @Letter@.
-Therefore, @Greek@ enums are a subset of type @Letter@ and are type compatible with enumeration @Letter@, but @Letter@ enums are not type compatible with enumeration @Greek@.
-
+
+void foo(Letter l);
+foo(Beta);			$\C{// foo(value(Beta))}$
+\end{cfa}
+Enumeration @Greek@ may have more or less enumerators than @Letter@, but the enum values \emph{must} be of a member of @Letter@.
+Therefore, the set of @Greek@ enum value in a subset of the value set of type @Letter@. 
+@Letter@ is type compatible with enumeration @Letter@ thanks to \CFA inserts value conversion whenever @Letter@ be used 
+in place of @Greek@. On the other hand, @Letter@ enums are not type compatible with enumeration @Greek@.
+As a result, @Greek@ becomes a logical subtype of @Letter@.
+
+Subset defines an implicit subtyping relationship between two \CFA enumerations. \CFA also has 
+containment inheritance for \CFA enumerations to explicit structure subtyping.
 
 \section{Inheritance}
@@ -238,6 +246,6 @@
 enum() E1 { B };								$\C{// B}$						
 enum() E2 { C, D };								$\C{// C D}$
-enum() E3 { inline E1, inline E2, E };			$\C{// {\color{red}[\(_{E1}\)} B {\color{red}]} {\color{red}[\(_{E2}\)} C, D {\color{red}]} E}$
-enum() E4 { A, inline E3, F};					$\C{// A {\color{blue}[\(_{E3}\)} {\color{red}[\(_{E1}\)} B {\color{red}]} {\color{red}[\(_{E2}\)} C, D {\color{red}]} E {\color{blue}]} F }$
+enum() E3 { inline E1, inline E2, E };			$\C{// {\color{red}[\(_{E1}\)} B {\color{red}]} {\color{red}[\(_{E2}\)} C D {\color{red}]} E}$
+enum() E4 { A, inline E3, F};					$\C{// A {\color{blue}[\(_{E3}\)} {\color{red}[\(_{E1}\)} B {\color{red}]} {\color{red}[\(_{E2}\)} C D {\color{red}]} E {\color{blue}]} F }$
 \end{cfa}
 In the example above, @B@ has the position 0 in @E1@ and @E3@, but it at the position 1 in @E4@ as @A@ taking the 0 in @E4@.