derived functor that preserves weak equivalences












3












$begingroup$


Suppose we have a functor $F:Arightarrow B$ between model categories.



1- Assume that F takes weak equivalences to weak equivalences and cofibrations to cofibrations, can we define the derived functor: $$Ho(F): Ho(A)rightarrow Ho(B) $$
2- Assume that F takes weak equivalences to weak equivalences, can we define the derived functor: $$Ho(F): Ho(A)rightarrow Ho(B) $$



It will be great to see the construction of such derived functor in detail. Thank you.










share|cite|improve this question









$endgroup$

















    3












    $begingroup$


    Suppose we have a functor $F:Arightarrow B$ between model categories.



    1- Assume that F takes weak equivalences to weak equivalences and cofibrations to cofibrations, can we define the derived functor: $$Ho(F): Ho(A)rightarrow Ho(B) $$
    2- Assume that F takes weak equivalences to weak equivalences, can we define the derived functor: $$Ho(F): Ho(A)rightarrow Ho(B) $$



    It will be great to see the construction of such derived functor in detail. Thank you.










    share|cite|improve this question









    $endgroup$















      3












      3








      3





      $begingroup$


      Suppose we have a functor $F:Arightarrow B$ between model categories.



      1- Assume that F takes weak equivalences to weak equivalences and cofibrations to cofibrations, can we define the derived functor: $$Ho(F): Ho(A)rightarrow Ho(B) $$
      2- Assume that F takes weak equivalences to weak equivalences, can we define the derived functor: $$Ho(F): Ho(A)rightarrow Ho(B) $$



      It will be great to see the construction of such derived functor in detail. Thank you.










      share|cite|improve this question









      $endgroup$




      Suppose we have a functor $F:Arightarrow B$ between model categories.



      1- Assume that F takes weak equivalences to weak equivalences and cofibrations to cofibrations, can we define the derived functor: $$Ho(F): Ho(A)rightarrow Ho(B) $$
      2- Assume that F takes weak equivalences to weak equivalences, can we define the derived functor: $$Ho(F): Ho(A)rightarrow Ho(B) $$



      It will be great to see the construction of such derived functor in detail. Thank you.







      reference-request model-categories






      share|cite|improve this question













      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked Nov 25 '18 at 18:39









      ABCABC

      755




      755






















          1 Answer
          1






          active

          oldest

          votes


















          6












          $begingroup$

          The answer is yes.



          Consider the functor $F:A to Ho(B)$ obtained by composing $F:A to B$ with the localization functor $B to Ho(B)$.



          Then this functor takes weak equivalences in $A$ to isomorphisms in $Ho(B)$,
          so by the universal property of localization, there is a functor $F':Ho(A) to Ho(B)$, such that $F cong F'circ Q$, where $Q:A to Ho(A)$ is the localization functor. This functor $F'$ is your derived functor.






          share|cite|improve this answer









          $endgroup$













            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: "504"
            };
            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%2fmathoverflow.net%2fquestions%2f316169%2fderived-functor-that-preserves-weak-equivalences%23new-answer', 'question_page');
            }
            );

            Post as a guest















            Required, but never shown

























            1 Answer
            1






            active

            oldest

            votes








            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            6












            $begingroup$

            The answer is yes.



            Consider the functor $F:A to Ho(B)$ obtained by composing $F:A to B$ with the localization functor $B to Ho(B)$.



            Then this functor takes weak equivalences in $A$ to isomorphisms in $Ho(B)$,
            so by the universal property of localization, there is a functor $F':Ho(A) to Ho(B)$, such that $F cong F'circ Q$, where $Q:A to Ho(A)$ is the localization functor. This functor $F'$ is your derived functor.






            share|cite|improve this answer









            $endgroup$


















              6












              $begingroup$

              The answer is yes.



              Consider the functor $F:A to Ho(B)$ obtained by composing $F:A to B$ with the localization functor $B to Ho(B)$.



              Then this functor takes weak equivalences in $A$ to isomorphisms in $Ho(B)$,
              so by the universal property of localization, there is a functor $F':Ho(A) to Ho(B)$, such that $F cong F'circ Q$, where $Q:A to Ho(A)$ is the localization functor. This functor $F'$ is your derived functor.






              share|cite|improve this answer









              $endgroup$
















                6












                6








                6





                $begingroup$

                The answer is yes.



                Consider the functor $F:A to Ho(B)$ obtained by composing $F:A to B$ with the localization functor $B to Ho(B)$.



                Then this functor takes weak equivalences in $A$ to isomorphisms in $Ho(B)$,
                so by the universal property of localization, there is a functor $F':Ho(A) to Ho(B)$, such that $F cong F'circ Q$, where $Q:A to Ho(A)$ is the localization functor. This functor $F'$ is your derived functor.






                share|cite|improve this answer









                $endgroup$



                The answer is yes.



                Consider the functor $F:A to Ho(B)$ obtained by composing $F:A to B$ with the localization functor $B to Ho(B)$.



                Then this functor takes weak equivalences in $A$ to isomorphisms in $Ho(B)$,
                so by the universal property of localization, there is a functor $F':Ho(A) to Ho(B)$, such that $F cong F'circ Q$, where $Q:A to Ho(A)$ is the localization functor. This functor $F'$ is your derived functor.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Nov 25 '18 at 19:01









                the Lthe L

                7551920




                7551920






























                    draft saved

                    draft discarded




















































                    Thanks for contributing an answer to MathOverflow!


                    • 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.




                    draft saved


                    draft discarded














                    StackExchange.ready(
                    function () {
                    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmathoverflow.net%2fquestions%2f316169%2fderived-functor-that-preserves-weak-equivalences%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

                    A CLEAN and SIMPLE way to add appendices to Table of Contents and bookmarks

                    Calculate evaluation metrics using cross_val_predict sklearn

                    Insert data from modal to MySQL (multiple modal on website)