Are stably rational surfaces all rational?Del pezzo surfaces in positive characteristicNumerically negative exceptional divisor on a surface.Universal property of blowing downStabilisers of group actionsAre stably birational varieties birational?Methods of showing a variety is stably rationalConic bundles on quartic del Pezzo surfacesPurely inseparable $k$-rational dominant maps between an absolutely irreducible $k$-surface and $mathbbP^2$Is an open subscheme of a rationally connected variety, rationally connected?Is there an odd degree unirational parametrization of a cubic threefold?

Are stably rational surfaces all rational?


Del pezzo surfaces in positive characteristicNumerically negative exceptional divisor on a surface.Universal property of blowing downStabilisers of group actionsAre stably birational varieties birational?Methods of showing a variety is stably rationalConic bundles on quartic del Pezzo surfacesPurely inseparable $k$-rational dominant maps between an absolutely irreducible $k$-surface and $mathbbP^2$Is an open subscheme of a rationally connected variety, rationally connected?Is there an odd degree unirational parametrization of a cubic threefold?













9












$begingroup$


Let $X$ be an irreducible surface such that $X times mathbbP^1$ is rational. Is it true that $X$ is rational?



If the field is not algebraically closed, the answer is no in general (see A. Beauville, J.-L. Colliot-Thélène, J.-J. Sansuc et Sir Peter Swinnerton-Dyer, Variétés stablement rationnelles non rationnelles, Ann. of Math. 121(1985) 283–318.).



If the field is algebraically closed of characteristic zero, the answer is yes.



What happens when the field is algebraically closed, of positive characteristic?



(one could ask the same for simply rationally connected surfaces).










share|cite|improve this question











$endgroup$











  • $begingroup$
    I imagine that this is a simple application of Castelnuovo's criterion, which is valid in all characteristics.
    $endgroup$
    – Daniel Loughran
    Mar 19 at 9:41






  • 2




    $begingroup$
    At least to me, the question does not exactly fit with the title. The question "are stably rational surfaces rational" is rather whether $XtimesmathbfP^n$ rational (for some $n$) implies $X$ rational?
    $endgroup$
    – YCor
    Mar 19 at 10:19
















9












$begingroup$


Let $X$ be an irreducible surface such that $X times mathbbP^1$ is rational. Is it true that $X$ is rational?



If the field is not algebraically closed, the answer is no in general (see A. Beauville, J.-L. Colliot-Thélène, J.-J. Sansuc et Sir Peter Swinnerton-Dyer, Variétés stablement rationnelles non rationnelles, Ann. of Math. 121(1985) 283–318.).



If the field is algebraically closed of characteristic zero, the answer is yes.



What happens when the field is algebraically closed, of positive characteristic?



(one could ask the same for simply rationally connected surfaces).










share|cite|improve this question











$endgroup$











  • $begingroup$
    I imagine that this is a simple application of Castelnuovo's criterion, which is valid in all characteristics.
    $endgroup$
    – Daniel Loughran
    Mar 19 at 9:41






  • 2




    $begingroup$
    At least to me, the question does not exactly fit with the title. The question "are stably rational surfaces rational" is rather whether $XtimesmathbfP^n$ rational (for some $n$) implies $X$ rational?
    $endgroup$
    – YCor
    Mar 19 at 10:19














9












9








9





$begingroup$


Let $X$ be an irreducible surface such that $X times mathbbP^1$ is rational. Is it true that $X$ is rational?



If the field is not algebraically closed, the answer is no in general (see A. Beauville, J.-L. Colliot-Thélène, J.-J. Sansuc et Sir Peter Swinnerton-Dyer, Variétés stablement rationnelles non rationnelles, Ann. of Math. 121(1985) 283–318.).



If the field is algebraically closed of characteristic zero, the answer is yes.



What happens when the field is algebraically closed, of positive characteristic?



(one could ask the same for simply rationally connected surfaces).










share|cite|improve this question











$endgroup$




Let $X$ be an irreducible surface such that $X times mathbbP^1$ is rational. Is it true that $X$ is rational?



If the field is not algebraically closed, the answer is no in general (see A. Beauville, J.-L. Colliot-Thélène, J.-J. Sansuc et Sir Peter Swinnerton-Dyer, Variétés stablement rationnelles non rationnelles, Ann. of Math. 121(1985) 283–318.).



If the field is algebraically closed of characteristic zero, the answer is yes.



What happens when the field is algebraically closed, of positive characteristic?



(one could ask the same for simply rationally connected surfaces).







ag.algebraic-geometry birational-geometry






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Mar 19 at 8:34







Jérémy Blanc

















asked Mar 19 at 8:21









Jérémy BlancJérémy Blanc

4,19411536




4,19411536











  • $begingroup$
    I imagine that this is a simple application of Castelnuovo's criterion, which is valid in all characteristics.
    $endgroup$
    – Daniel Loughran
    Mar 19 at 9:41






  • 2




    $begingroup$
    At least to me, the question does not exactly fit with the title. The question "are stably rational surfaces rational" is rather whether $XtimesmathbfP^n$ rational (for some $n$) implies $X$ rational?
    $endgroup$
    – YCor
    Mar 19 at 10:19

















  • $begingroup$
    I imagine that this is a simple application of Castelnuovo's criterion, which is valid in all characteristics.
    $endgroup$
    – Daniel Loughran
    Mar 19 at 9:41






  • 2




    $begingroup$
    At least to me, the question does not exactly fit with the title. The question "are stably rational surfaces rational" is rather whether $XtimesmathbfP^n$ rational (for some $n$) implies $X$ rational?
    $endgroup$
    – YCor
    Mar 19 at 10:19
















$begingroup$
I imagine that this is a simple application of Castelnuovo's criterion, which is valid in all characteristics.
$endgroup$
– Daniel Loughran
Mar 19 at 9:41




$begingroup$
I imagine that this is a simple application of Castelnuovo's criterion, which is valid in all characteristics.
$endgroup$
– Daniel Loughran
Mar 19 at 9:41




2




2




$begingroup$
At least to me, the question does not exactly fit with the title. The question "are stably rational surfaces rational" is rather whether $XtimesmathbfP^n$ rational (for some $n$) implies $X$ rational?
$endgroup$
– YCor
Mar 19 at 10:19





$begingroup$
At least to me, the question does not exactly fit with the title. The question "are stably rational surfaces rational" is rather whether $XtimesmathbfP^n$ rational (for some $n$) implies $X$ rational?
$endgroup$
– YCor
Mar 19 at 10:19











1 Answer
1






active

oldest

votes


















12












$begingroup$

The result is true in all characteristics. See O. Zariski, Illinois J. Math. 2(1958), 303-315.






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%2f325752%2fare-stably-rational-surfaces-all-rational%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









    12












    $begingroup$

    The result is true in all characteristics. See O. Zariski, Illinois J. Math. 2(1958), 303-315.






    share|cite|improve this answer









    $endgroup$

















      12












      $begingroup$

      The result is true in all characteristics. See O. Zariski, Illinois J. Math. 2(1958), 303-315.






      share|cite|improve this answer









      $endgroup$















        12












        12








        12





        $begingroup$

        The result is true in all characteristics. See O. Zariski, Illinois J. Math. 2(1958), 303-315.






        share|cite|improve this answer









        $endgroup$



        The result is true in all characteristics. See O. Zariski, Illinois J. Math. 2(1958), 303-315.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Mar 19 at 9:14









        Laurent Moret-BaillyLaurent Moret-Bailly

        14.5k14769




        14.5k14769



























            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%2f325752%2fare-stably-rational-surfaces-all-rational%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

            Marja Vauras Lähteet | Aiheesta muualla | NavigointivalikkoMarja Vauras Turun yliopiston tutkimusportaalissaInfobox OKSuomalaisen Tiedeakatemian varsinaiset jäsenetKasvatustieteiden tiedekunnan dekaanit ja muu johtoMarja VaurasKoulutusvienti on kestävyys- ja ketteryyslaji (2.5.2017)laajentamallaWorldCat Identities0000 0001 0855 9405n86069603utb201588738523620927

            Which is better: GPT or RelGAN for text generation?2019 Community Moderator ElectionWhat is the difference between TextGAN and LM for text generation?GANs (generative adversarial networks) possible for text as well?Generator loss not decreasing- text to image synthesisChoosing a right algorithm for template-based text generationHow should I format input and output for text generation with LSTMsGumbel Softmax vs Vanilla Softmax for GAN trainingWhich neural network to choose for classification from text/speech?NLP text autoencoder that generates text in poetic meterWhat is the interpretation of the expectation notation in the GAN formulation?What is the difference between TextGAN and LM for text generation?How to prepare the data for text generation task

            Is flight data recorder erased after every flight?When are black boxes used?What protects the location beacon (pinger) of a flight data recorder?Is there anywhere I can pick up raw flight data recorder information?Who legally owns the Flight Data Recorder?Constructing flight recorder dataWhy are FDRs and CVRs still two separate physical devices?What are the data elements shown on the GE235 flight data recorder (FDR) plot?Are CVR and FDR reset after every flight?What is the format of data stored by a Flight Data Recorder?How much data is stored in the flight data recorder per hour in a typical flight of an A380?Is a smart flight data recorder possible?