equal
deleted
inserted
replaced
511 \begin{equation}\label{inv2} |
511 \begin{equation}\label{inv2} |
512 @{text "X\<^isub>1 = \<calL>(Y\<^isub>1\<^isub>1, CHAR c\<^isub>1\<^isub>1) \<union> \<dots> \<union> \<calL>(Y\<^isub>1\<^isub>p, CHAR c\<^isub>1\<^isub>p) \<union> \<calL>(\<lambda>(EMPTY))"}. |
512 @{text "X\<^isub>1 = \<calL>(Y\<^isub>1\<^isub>1, CHAR c\<^isub>1\<^isub>1) \<union> \<dots> \<union> \<calL>(Y\<^isub>1\<^isub>p, CHAR c\<^isub>1\<^isub>p) \<union> \<calL>(\<lambda>(EMPTY))"}. |
513 \end{equation} |
513 \end{equation} |
514 |
514 |
515 \noindent |
515 \noindent |
516 The reason for adding the @{text \<lambda>}-marker to our initial equational system is |
516 holds. The reason for adding the @{text \<lambda>}-marker to our initial equational system is |
517 to obtain this equation: it only holds with the marker, since none of |
517 to obtain this equation: it only holds with the marker, since none of |
518 the other terms contain the empty string. The point of the initial equational system is |
518 the other terms contain the empty string. The point of the initial equational system is |
519 that solving it means we will be able to extract a regular expression for every equivalence class. |
519 that solving it means we will be able to extract a regular expression for every equivalence class. |
520 |
520 |
521 Our representation for the equations in Isabelle/HOL are pairs, |
521 Our representation for the equations in Isabelle/HOL are pairs, |
719 \end{tabular} |
719 \end{tabular} |
720 \end{center} |
720 \end{center} |
721 |
721 |
722 \noindent |
722 \noindent |
723 The first two ensure that the equational system is always finite (number of equations |
723 The first two ensure that the equational system is always finite (number of equations |
724 and number of terms in each equation); the second makes sure the `meaning' of the |
724 and number of terms in each equation); the third makes sure the `meaning' of the |
725 equations is preserved under our transformations. The other properties are a bit more |
725 equations is preserved under our transformations. The other properties are a bit more |
726 technical, but are needed to get our proof through. Distinctness states that every |
726 technical, but are needed to get our proof through. Distinctness states that every |
727 equation in the system is distinct. @{text Ardenable} ensures that we can always |
727 equation in the system is distinct. @{text Ardenable} ensures that we can always |
728 apply the @{text Arden} operation. |
728 apply the @{text Arden} operation. |
729 The last property states that every @{text rhs} can only contain equivalence classes |
729 The last property states that every @{text rhs} can only contain equivalence classes |
873 |
873 |
874 section {* Myhill-Nerode, Second Part *} |
874 section {* Myhill-Nerode, Second Part *} |
875 |
875 |
876 text {* |
876 text {* |
877 We will prove in this section the second part of the Myhill-Nerode |
877 We will prove in this section the second part of the Myhill-Nerode |
878 theorem. It can be formulated in our setting as follows. |
878 theorem. It can be formulated in our setting as follows: |
879 |
879 |
880 \begin{theorem} |
880 \begin{theorem} |
881 Given @{text "r"} is a regular expression, then @{thm Myhill_Nerode2}. |
881 Given @{text "r"} is a regular expression, then @{thm Myhill_Nerode2}. |
882 \end{theorem} |
882 \end{theorem} |
883 |
883 |