Is the geometrical meaning of cup product still valid for subvarieties?












4












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It is known that cup product is Poincaré dual to the intersection. I'm referring to the following fact: if $X$ is a closed, oriented smooth manifold and $A, B$ are transverse-intersecting oriented submanifolds of codimension $i, j$ respectively, then



$$[A cap B]^* = [A]^* smile [B]^* in H^{i+j}(X)space ,$$



where the asterisk denotes Poincaré dual.



My question: is the same true if we take $A, B$ to be transverse-intersecting algebraic varieties? (And does that even make sense? I think that an algebraic subvariety defines an homology class given by the pushforward of the inclusion of the top class, and therefore it makes sense; but correct me if I'm wrong).



For context: I'm studying Schubert calculus, and I want to use this fact when $A, B$ are Schubert varieties, but I think Schubert varieties aren't smooth manifolds in general, since they contain singular points.










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    4












    $begingroup$


    It is known that cup product is Poincaré dual to the intersection. I'm referring to the following fact: if $X$ is a closed, oriented smooth manifold and $A, B$ are transverse-intersecting oriented submanifolds of codimension $i, j$ respectively, then



    $$[A cap B]^* = [A]^* smile [B]^* in H^{i+j}(X)space ,$$



    where the asterisk denotes Poincaré dual.



    My question: is the same true if we take $A, B$ to be transverse-intersecting algebraic varieties? (And does that even make sense? I think that an algebraic subvariety defines an homology class given by the pushforward of the inclusion of the top class, and therefore it makes sense; but correct me if I'm wrong).



    For context: I'm studying Schubert calculus, and I want to use this fact when $A, B$ are Schubert varieties, but I think Schubert varieties aren't smooth manifolds in general, since they contain singular points.










    share|cite|improve this question











    $endgroup$















      4












      4








      4


      1



      $begingroup$


      It is known that cup product is Poincaré dual to the intersection. I'm referring to the following fact: if $X$ is a closed, oriented smooth manifold and $A, B$ are transverse-intersecting oriented submanifolds of codimension $i, j$ respectively, then



      $$[A cap B]^* = [A]^* smile [B]^* in H^{i+j}(X)space ,$$



      where the asterisk denotes Poincaré dual.



      My question: is the same true if we take $A, B$ to be transverse-intersecting algebraic varieties? (And does that even make sense? I think that an algebraic subvariety defines an homology class given by the pushforward of the inclusion of the top class, and therefore it makes sense; but correct me if I'm wrong).



      For context: I'm studying Schubert calculus, and I want to use this fact when $A, B$ are Schubert varieties, but I think Schubert varieties aren't smooth manifolds in general, since they contain singular points.










      share|cite|improve this question











      $endgroup$




      It is known that cup product is Poincaré dual to the intersection. I'm referring to the following fact: if $X$ is a closed, oriented smooth manifold and $A, B$ are transverse-intersecting oriented submanifolds of codimension $i, j$ respectively, then



      $$[A cap B]^* = [A]^* smile [B]^* in H^{i+j}(X)space ,$$



      where the asterisk denotes Poincaré dual.



      My question: is the same true if we take $A, B$ to be transverse-intersecting algebraic varieties? (And does that even make sense? I think that an algebraic subvariety defines an homology class given by the pushforward of the inclusion of the top class, and therefore it makes sense; but correct me if I'm wrong).



      For context: I'm studying Schubert calculus, and I want to use this fact when $A, B$ are Schubert varieties, but I think Schubert varieties aren't smooth manifolds in general, since they contain singular points.







      algebraic-geometry algebraic-topology schubert-calculus






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      edited Jan 2 at 0:50









      Matt Samuel

      38.7k63769




      38.7k63769










      asked Jul 10 '17 at 13:52









      un umile appassionatoun umile appassionato

      367316




      367316






















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          $begingroup$

          This is basically the approach via stratifolds developed by Kreck; see




          Kreck, Matthias.
          Differential algebraic topology.
          From stratifolds to exotic spheres. Graduate Studies in Mathematics, 110. American Mathematical Society, Providence, RI, 2010




          and




          Bunke, Ulrich; Kreck, Matthias; Schick, Thomas. A geometric description of differential cohomology. Ann. Math. Blaise Pascal 17 (2010), no. 1, 1–16.







          share|cite|improve this answer











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            1 Answer
            1






            active

            oldest

            votes








            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            3












            $begingroup$

            This is basically the approach via stratifolds developed by Kreck; see




            Kreck, Matthias.
            Differential algebraic topology.
            From stratifolds to exotic spheres. Graduate Studies in Mathematics, 110. American Mathematical Society, Providence, RI, 2010




            and




            Bunke, Ulrich; Kreck, Matthias; Schick, Thomas. A geometric description of differential cohomology. Ann. Math. Blaise Pascal 17 (2010), no. 1, 1–16.







            share|cite|improve this answer











            $endgroup$


















              3












              $begingroup$

              This is basically the approach via stratifolds developed by Kreck; see




              Kreck, Matthias.
              Differential algebraic topology.
              From stratifolds to exotic spheres. Graduate Studies in Mathematics, 110. American Mathematical Society, Providence, RI, 2010




              and




              Bunke, Ulrich; Kreck, Matthias; Schick, Thomas. A geometric description of differential cohomology. Ann. Math. Blaise Pascal 17 (2010), no. 1, 1–16.







              share|cite|improve this answer











              $endgroup$
















                3












                3








                3





                $begingroup$

                This is basically the approach via stratifolds developed by Kreck; see




                Kreck, Matthias.
                Differential algebraic topology.
                From stratifolds to exotic spheres. Graduate Studies in Mathematics, 110. American Mathematical Society, Providence, RI, 2010




                and




                Bunke, Ulrich; Kreck, Matthias; Schick, Thomas. A geometric description of differential cohomology. Ann. Math. Blaise Pascal 17 (2010), no. 1, 1–16.







                share|cite|improve this answer











                $endgroup$



                This is basically the approach via stratifolds developed by Kreck; see




                Kreck, Matthias.
                Differential algebraic topology.
                From stratifolds to exotic spheres. Graduate Studies in Mathematics, 110. American Mathematical Society, Providence, RI, 2010




                and




                Bunke, Ulrich; Kreck, Matthias; Schick, Thomas. A geometric description of differential cohomology. Ann. Math. Blaise Pascal 17 (2010), no. 1, 1–16.








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                share|cite|improve this answer








                edited Jul 10 '17 at 14:08

























                answered Jul 10 '17 at 14:01









                Mikhail KatzMikhail Katz

                30.7k14398




                30.7k14398






























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