prove or disprove if the following language is regular language












3














for $A,Bsubseteq{0,1}^*$ regular languages



prove or disprove that $L_2$ is a regular language:



$L_2 = {x in A | exists y in B : |x|_1 =|y|_1 }$



$|x|_1$ means the number of appearances of 1 in the word.



if $L_2$ regular language demonstrate his automata, else disprove with pump lemma or with clousre properties.



I think $L_2$ is a regular language because I can choose $A=B$ for example and I'll get regular language or for example $B={0,1}^*$.



I am not sure how to demonstrate his automata.










share|cite|improve this question
























  • Are $A$ and $B$ regular languages? Also, I assume prove that "$L_2$ is a formal language" is a typo, since this would be trivial and doesn't match the title. Should it say "regular language"?
    – Joey Kilpatrick
    Nov 25 at 4:02












  • @JoeyKilpatrick you are right, edited.
    – UltimateMath
    Nov 25 at 7:43












  • Let $B' = {s in Sigma^* mid |s|_1 = |y|_1 text{ for some } y in B}$, then $L_2 = A cap B'$, can you find an automatum for $B'$?
    – Alex Vong
    Nov 25 at 8:01


















3














for $A,Bsubseteq{0,1}^*$ regular languages



prove or disprove that $L_2$ is a regular language:



$L_2 = {x in A | exists y in B : |x|_1 =|y|_1 }$



$|x|_1$ means the number of appearances of 1 in the word.



if $L_2$ regular language demonstrate his automata, else disprove with pump lemma or with clousre properties.



I think $L_2$ is a regular language because I can choose $A=B$ for example and I'll get regular language or for example $B={0,1}^*$.



I am not sure how to demonstrate his automata.










share|cite|improve this question
























  • Are $A$ and $B$ regular languages? Also, I assume prove that "$L_2$ is a formal language" is a typo, since this would be trivial and doesn't match the title. Should it say "regular language"?
    – Joey Kilpatrick
    Nov 25 at 4:02












  • @JoeyKilpatrick you are right, edited.
    – UltimateMath
    Nov 25 at 7:43












  • Let $B' = {s in Sigma^* mid |s|_1 = |y|_1 text{ for some } y in B}$, then $L_2 = A cap B'$, can you find an automatum for $B'$?
    – Alex Vong
    Nov 25 at 8:01
















3












3








3







for $A,Bsubseteq{0,1}^*$ regular languages



prove or disprove that $L_2$ is a regular language:



$L_2 = {x in A | exists y in B : |x|_1 =|y|_1 }$



$|x|_1$ means the number of appearances of 1 in the word.



if $L_2$ regular language demonstrate his automata, else disprove with pump lemma or with clousre properties.



I think $L_2$ is a regular language because I can choose $A=B$ for example and I'll get regular language or for example $B={0,1}^*$.



I am not sure how to demonstrate his automata.










share|cite|improve this question















for $A,Bsubseteq{0,1}^*$ regular languages



prove or disprove that $L_2$ is a regular language:



$L_2 = {x in A | exists y in B : |x|_1 =|y|_1 }$



$|x|_1$ means the number of appearances of 1 in the word.



if $L_2$ regular language demonstrate his automata, else disprove with pump lemma or with clousre properties.



I think $L_2$ is a regular language because I can choose $A=B$ for example and I'll get regular language or for example $B={0,1}^*$.



I am not sure how to demonstrate his automata.







formal-languages automata






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Nov 25 at 7:40

























asked Nov 24 at 22:09









UltimateMath

746




746












  • Are $A$ and $B$ regular languages? Also, I assume prove that "$L_2$ is a formal language" is a typo, since this would be trivial and doesn't match the title. Should it say "regular language"?
    – Joey Kilpatrick
    Nov 25 at 4:02












  • @JoeyKilpatrick you are right, edited.
    – UltimateMath
    Nov 25 at 7:43












  • Let $B' = {s in Sigma^* mid |s|_1 = |y|_1 text{ for some } y in B}$, then $L_2 = A cap B'$, can you find an automatum for $B'$?
    – Alex Vong
    Nov 25 at 8:01




















  • Are $A$ and $B$ regular languages? Also, I assume prove that "$L_2$ is a formal language" is a typo, since this would be trivial and doesn't match the title. Should it say "regular language"?
    – Joey Kilpatrick
    Nov 25 at 4:02












  • @JoeyKilpatrick you are right, edited.
    – UltimateMath
    Nov 25 at 7:43












  • Let $B' = {s in Sigma^* mid |s|_1 = |y|_1 text{ for some } y in B}$, then $L_2 = A cap B'$, can you find an automatum for $B'$?
    – Alex Vong
    Nov 25 at 8:01


















Are $A$ and $B$ regular languages? Also, I assume prove that "$L_2$ is a formal language" is a typo, since this would be trivial and doesn't match the title. Should it say "regular language"?
– Joey Kilpatrick
Nov 25 at 4:02






Are $A$ and $B$ regular languages? Also, I assume prove that "$L_2$ is a formal language" is a typo, since this would be trivial and doesn't match the title. Should it say "regular language"?
– Joey Kilpatrick
Nov 25 at 4:02














@JoeyKilpatrick you are right, edited.
– UltimateMath
Nov 25 at 7:43






@JoeyKilpatrick you are right, edited.
– UltimateMath
Nov 25 at 7:43














Let $B' = {s in Sigma^* mid |s|_1 = |y|_1 text{ for some } y in B}$, then $L_2 = A cap B'$, can you find an automatum for $B'$?
– Alex Vong
Nov 25 at 8:01






Let $B' = {s in Sigma^* mid |s|_1 = |y|_1 text{ for some } y in B}$, then $L_2 = A cap B'$, can you find an automatum for $B'$?
– Alex Vong
Nov 25 at 8:01












2 Answers
2






active

oldest

votes


















3














I am not entire sure if my approach work, but here we go:
Firstly, we observe that we can write $L_2 = A cap B'$ where $B' = {s in Sigma^* mid |s|_1 = |y|_1 text{ for some } y in B}$. Since we can create a FSA for the intersection of two regular languages, it suffices to find a FSA for $B'$.



Before proceeding, consider a more concrete description of $B'$. Note that we can write $$B' = {0^{alpha_0} 1 0^{alpha_1} 1 0^{alpha_2} dots 1 0^{alpha_{|y|_1}} mid alpha_j in mathbb{N}, y in B}$$ Intuitively, $B'$ is constructed by taking all strings in $B$, chops away all $0$'s, and adding back any number of $0$'s in between.



Now given a FSA $M$ for $B$, we can construct a corresponding FSA $M'$ for $B'$ by the following transformation:



Case 1:
B case 1
should be converted to
B' case 1



Case 2:
B case 2
Nothing needs to be changed.



Case 3:
B case 3
should be converted to
B' case 3



Case 4:
B case 4
Nothing needs to be changed.



This completes the FSA.






share|cite|improve this answer





























    2














    Let $pi: {0,1}^* to 1^*$ be the monoid morphism defined by $pi(u) = |u|_1$. Since regular languages are closed under morphisms and inverses of morphisms, $R =pi(B)$ is regular and $L_2 = A cap pi^{-1}(R)$ is regular.






    share|cite|improve this answer























      Your Answer





      StackExchange.ifUsing("editor", function () {
      return StackExchange.using("mathjaxEditing", function () {
      StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
      StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
      });
      });
      }, "mathjax-editing");

      StackExchange.ready(function() {
      var channelOptions = {
      tags: "".split(" "),
      id: "69"
      };
      initTagRenderer("".split(" "), "".split(" "), channelOptions);

      StackExchange.using("externalEditor", function() {
      // Have to fire editor after snippets, if snippets enabled
      if (StackExchange.settings.snippets.snippetsEnabled) {
      StackExchange.using("snippets", function() {
      createEditor();
      });
      }
      else {
      createEditor();
      }
      });

      function createEditor() {
      StackExchange.prepareEditor({
      heartbeatType: 'answer',
      autoActivateHeartbeat: false,
      convertImagesToLinks: true,
      noModals: true,
      showLowRepImageUploadWarning: true,
      reputationToPostImages: 10,
      bindNavPrevention: true,
      postfix: "",
      imageUploader: {
      brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
      contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
      allowUrls: true
      },
      noCode: true, onDemand: true,
      discardSelector: ".discard-answer"
      ,immediatelyShowMarkdownHelp:true
      });


      }
      });














      draft saved

      draft discarded


















      StackExchange.ready(
      function () {
      StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3012154%2fprove-or-disprove-if-the-following-language-is-regular-language%23new-answer', 'question_page');
      }
      );

      Post as a guest















      Required, but never shown

























      2 Answers
      2






      active

      oldest

      votes








      2 Answers
      2






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      3














      I am not entire sure if my approach work, but here we go:
      Firstly, we observe that we can write $L_2 = A cap B'$ where $B' = {s in Sigma^* mid |s|_1 = |y|_1 text{ for some } y in B}$. Since we can create a FSA for the intersection of two regular languages, it suffices to find a FSA for $B'$.



      Before proceeding, consider a more concrete description of $B'$. Note that we can write $$B' = {0^{alpha_0} 1 0^{alpha_1} 1 0^{alpha_2} dots 1 0^{alpha_{|y|_1}} mid alpha_j in mathbb{N}, y in B}$$ Intuitively, $B'$ is constructed by taking all strings in $B$, chops away all $0$'s, and adding back any number of $0$'s in between.



      Now given a FSA $M$ for $B$, we can construct a corresponding FSA $M'$ for $B'$ by the following transformation:



      Case 1:
      B case 1
      should be converted to
      B' case 1



      Case 2:
      B case 2
      Nothing needs to be changed.



      Case 3:
      B case 3
      should be converted to
      B' case 3



      Case 4:
      B case 4
      Nothing needs to be changed.



      This completes the FSA.






      share|cite|improve this answer


























        3














        I am not entire sure if my approach work, but here we go:
        Firstly, we observe that we can write $L_2 = A cap B'$ where $B' = {s in Sigma^* mid |s|_1 = |y|_1 text{ for some } y in B}$. Since we can create a FSA for the intersection of two regular languages, it suffices to find a FSA for $B'$.



        Before proceeding, consider a more concrete description of $B'$. Note that we can write $$B' = {0^{alpha_0} 1 0^{alpha_1} 1 0^{alpha_2} dots 1 0^{alpha_{|y|_1}} mid alpha_j in mathbb{N}, y in B}$$ Intuitively, $B'$ is constructed by taking all strings in $B$, chops away all $0$'s, and adding back any number of $0$'s in between.



        Now given a FSA $M$ for $B$, we can construct a corresponding FSA $M'$ for $B'$ by the following transformation:



        Case 1:
        B case 1
        should be converted to
        B' case 1



        Case 2:
        B case 2
        Nothing needs to be changed.



        Case 3:
        B case 3
        should be converted to
        B' case 3



        Case 4:
        B case 4
        Nothing needs to be changed.



        This completes the FSA.






        share|cite|improve this answer
























          3












          3








          3






          I am not entire sure if my approach work, but here we go:
          Firstly, we observe that we can write $L_2 = A cap B'$ where $B' = {s in Sigma^* mid |s|_1 = |y|_1 text{ for some } y in B}$. Since we can create a FSA for the intersection of two regular languages, it suffices to find a FSA for $B'$.



          Before proceeding, consider a more concrete description of $B'$. Note that we can write $$B' = {0^{alpha_0} 1 0^{alpha_1} 1 0^{alpha_2} dots 1 0^{alpha_{|y|_1}} mid alpha_j in mathbb{N}, y in B}$$ Intuitively, $B'$ is constructed by taking all strings in $B$, chops away all $0$'s, and adding back any number of $0$'s in between.



          Now given a FSA $M$ for $B$, we can construct a corresponding FSA $M'$ for $B'$ by the following transformation:



          Case 1:
          B case 1
          should be converted to
          B' case 1



          Case 2:
          B case 2
          Nothing needs to be changed.



          Case 3:
          B case 3
          should be converted to
          B' case 3



          Case 4:
          B case 4
          Nothing needs to be changed.



          This completes the FSA.






          share|cite|improve this answer












          I am not entire sure if my approach work, but here we go:
          Firstly, we observe that we can write $L_2 = A cap B'$ where $B' = {s in Sigma^* mid |s|_1 = |y|_1 text{ for some } y in B}$. Since we can create a FSA for the intersection of two regular languages, it suffices to find a FSA for $B'$.



          Before proceeding, consider a more concrete description of $B'$. Note that we can write $$B' = {0^{alpha_0} 1 0^{alpha_1} 1 0^{alpha_2} dots 1 0^{alpha_{|y|_1}} mid alpha_j in mathbb{N}, y in B}$$ Intuitively, $B'$ is constructed by taking all strings in $B$, chops away all $0$'s, and adding back any number of $0$'s in between.



          Now given a FSA $M$ for $B$, we can construct a corresponding FSA $M'$ for $B'$ by the following transformation:



          Case 1:
          B case 1
          should be converted to
          B' case 1



          Case 2:
          B case 2
          Nothing needs to be changed.



          Case 3:
          B case 3
          should be converted to
          B' case 3



          Case 4:
          B case 4
          Nothing needs to be changed.



          This completes the FSA.







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Nov 25 at 12:05









          Alex Vong

          1,227819




          1,227819























              2














              Let $pi: {0,1}^* to 1^*$ be the monoid morphism defined by $pi(u) = |u|_1$. Since regular languages are closed under morphisms and inverses of morphisms, $R =pi(B)$ is regular and $L_2 = A cap pi^{-1}(R)$ is regular.






              share|cite|improve this answer




























                2














                Let $pi: {0,1}^* to 1^*$ be the monoid morphism defined by $pi(u) = |u|_1$. Since regular languages are closed under morphisms and inverses of morphisms, $R =pi(B)$ is regular and $L_2 = A cap pi^{-1}(R)$ is regular.






                share|cite|improve this answer


























                  2












                  2








                  2






                  Let $pi: {0,1}^* to 1^*$ be the monoid morphism defined by $pi(u) = |u|_1$. Since regular languages are closed under morphisms and inverses of morphisms, $R =pi(B)$ is regular and $L_2 = A cap pi^{-1}(R)$ is regular.






                  share|cite|improve this answer














                  Let $pi: {0,1}^* to 1^*$ be the monoid morphism defined by $pi(u) = |u|_1$. Since regular languages are closed under morphisms and inverses of morphisms, $R =pi(B)$ is regular and $L_2 = A cap pi^{-1}(R)$ is regular.







                  share|cite|improve this answer














                  share|cite|improve this answer



                  share|cite|improve this answer








                  edited Nov 25 at 12:22

























                  answered Nov 25 at 11:23









                  J.-E. Pin

                  18.3k21754




                  18.3k21754






























                      draft saved

                      draft discarded




















































                      Thanks for contributing an answer to Mathematics Stack Exchange!


                      • Please be sure to answer the question. Provide details and share your research!

                      But avoid



                      • Asking for help, clarification, or responding to other answers.

                      • Making statements based on opinion; back them up with references or personal experience.


                      Use MathJax to format equations. MathJax reference.


                      To learn more, see our tips on writing great answers.





                      Some of your past answers have not been well-received, and you're in danger of being blocked from answering.


                      Please pay close attention to the following guidance:


                      • Please be sure to answer the question. Provide details and share your research!

                      But avoid



                      • Asking for help, clarification, or responding to other answers.

                      • Making statements based on opinion; back them up with references or personal experience.


                      To learn more, see our tips on writing great answers.




                      draft saved


                      draft discarded














                      StackExchange.ready(
                      function () {
                      StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3012154%2fprove-or-disprove-if-the-following-language-is-regular-language%23new-answer', 'question_page');
                      }
                      );

                      Post as a guest















                      Required, but never shown





















































                      Required, but never shown














                      Required, but never shown












                      Required, but never shown







                      Required, but never shown

































                      Required, but never shown














                      Required, but never shown












                      Required, but never shown







                      Required, but never shown







                      Popular posts from this blog

                      Le Mesnil-Réaume

                      Ida-Boy-Ed-Garten

                      web3.py web3.isConnected() returns false always