thys/Journal/Paper.thy
changeset 275 deea42c83c9e
parent 274 692b62426677
child 280 c840a99a3e05
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   221 \end{center}
   221 \end{center}
   222 
   222 
   223 \noindent where @{const Stars}, @{text Left}, @{text Right} and @{text
   223 \noindent where @{const Stars}, @{text Left}, @{text Right} and @{text
   224 Char} are constructors for values. @{text Stars} records how many
   224 Char} are constructors for values. @{text Stars} records how many
   225 iterations were used; @{text Left}, respectively @{text Right}, which
   225 iterations were used; @{text Left}, respectively @{text Right}, which
   226 alternative is used. This `tree view' leads naturally to the
   226 alternative is used. This `tree view' leads naturally to the idea that
   227 idea that regular expressions act as types and values as inhabiting
   227 regular expressions act as types and values as inhabiting those types
   228 those types. This view was first put forward by ???. The value for the
   228 (see, for example, \cite{HosoyaVouillonPierce2005}).  The value for
   229 single `iteration', i.e.~the POSIX value, would look as follows
   229 the single `iteration', i.e.~the POSIX value, would look as follows
   230 
   230 
   231 \begin{center}
   231 \begin{center}
   232 @{term "Stars [Seq (Char x) (Char y)]"}
   232 @{term "Stars [Seq (Char x) (Char y)]"}
   233 \end{center}
   233 \end{center}
   234 
   234 
  1251   a single statement would require an additional assumption about the
  1251   a single statement would require an additional assumption about the
  1252   two values @{term "Seq v\<^sub>1 v\<^sub>2"} and @{term "Seq w\<^sub>1 w\<^sub>2"}
  1252   two values @{term "Seq v\<^sub>1 v\<^sub>2"} and @{term "Seq w\<^sub>1 w\<^sub>2"}
  1253   being inhabited by the same regular expression. The
  1253   being inhabited by the same regular expression. The
  1254   complexity of the proofs involved seems to not justify such a
  1254   complexity of the proofs involved seems to not justify such a
  1255   `cleaner' single statement. The statements given are just the properties that
  1255   `cleaner' single statement. The statements given are just the properties that
  1256   allow us to establish our theorems. The proofs for Proposition~\ref{ordintros}
  1256   allow us to establish our theorems without any difficulty. The proofs 
  1257   are routine.
  1257   for Proposition~\ref{ordintros} are routine.
  1258  
  1258  
  1259 
  1259 
  1260   Next we establish how Okui and Suzuki's orderings relate to our
  1260   Next we establish how Okui and Suzuki's orderings relate to our
  1261   definition of POSIX values.  Given a @{text POSIX} value @{text "v\<^sub>1"}
  1261   definition of POSIX values.  Given a @{text POSIX} value @{text "v\<^sub>1"}
  1262   for @{text r} and @{text s}, then any other lexical value @{text
  1262   for @{text r} and @{text s}, then any other lexical value @{text