Two questions about Schubert calculus and Schur functions.












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I am reading the file. I have a question on pae 28. How to prove that $[X_{{2,4}}] = S_{(1)} = x_1 + x_2 + cdots$ and $S_{(1)}^4 = 2 S_{(2,2)} + S_{(3,1)} + S_{(2,1,1)}$? I tried to verify $S_{(1)}^4 = 2 S_{(2,2)} + S_{(3,1)} + S_{(2,1,1)}$ directly. But on the left hand side we have a term $x_1^4$ and it seems that on the right hand side we don't have $x_1^4$. Thank you very much.










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    $begingroup$


    I am reading the file. I have a question on pae 28. How to prove that $[X_{{2,4}}] = S_{(1)} = x_1 + x_2 + cdots$ and $S_{(1)}^4 = 2 S_{(2,2)} + S_{(3,1)} + S_{(2,1,1)}$? I tried to verify $S_{(1)}^4 = 2 S_{(2,2)} + S_{(3,1)} + S_{(2,1,1)}$ directly. But on the left hand side we have a term $x_1^4$ and it seems that on the right hand side we don't have $x_1^4$. Thank you very much.










    share|cite|improve this question











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      2


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      $begingroup$


      I am reading the file. I have a question on pae 28. How to prove that $[X_{{2,4}}] = S_{(1)} = x_1 + x_2 + cdots$ and $S_{(1)}^4 = 2 S_{(2,2)} + S_{(3,1)} + S_{(2,1,1)}$? I tried to verify $S_{(1)}^4 = 2 S_{(2,2)} + S_{(3,1)} + S_{(2,1,1)}$ directly. But on the left hand side we have a term $x_1^4$ and it seems that on the right hand side we don't have $x_1^4$. Thank you very much.










      share|cite|improve this question











      $endgroup$




      I am reading the file. I have a question on pae 28. How to prove that $[X_{{2,4}}] = S_{(1)} = x_1 + x_2 + cdots$ and $S_{(1)}^4 = 2 S_{(2,2)} + S_{(3,1)} + S_{(2,1,1)}$? I tried to verify $S_{(1)}^4 = 2 S_{(2,2)} + S_{(3,1)} + S_{(2,1,1)}$ directly. But on the left hand side we have a term $x_1^4$ and it seems that on the right hand side we don't have $x_1^4$. Thank you very much.







      geometry algebraic-geometry representation-theory schubert-calculus






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      edited Jan 2 at 1:03









      darij grinberg

      10.4k33062




      10.4k33062










      asked Aug 12 '15 at 7:09









      LJRLJR

      6,57341749




      6,57341749






















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          That formula is not correct. The correct decomposition is $$S_{(1)}^4 = S_{(4)} + 3 S_{(3,1)} + 2 S_{(2,2)} + 3 S_{(2,1,1)} + S_{(1,1,1,1)}.$$ This can be calculated by the formula $$S_lambda cdot S_{(1)} = sum_{mu} S_{mu}$$ where $mu$ ranges over all partitions obtained from $lambda$ by adding a single box. (Pieri's formula)






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            $begingroup$

            That formula is not correct. The correct decomposition is $$S_{(1)}^4 = S_{(4)} + 3 S_{(3,1)} + 2 S_{(2,2)} + 3 S_{(2,1,1)} + S_{(1,1,1,1)}.$$ This can be calculated by the formula $$S_lambda cdot S_{(1)} = sum_{mu} S_{mu}$$ where $mu$ ranges over all partitions obtained from $lambda$ by adding a single box. (Pieri's formula)






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              3












              $begingroup$

              That formula is not correct. The correct decomposition is $$S_{(1)}^4 = S_{(4)} + 3 S_{(3,1)} + 2 S_{(2,2)} + 3 S_{(2,1,1)} + S_{(1,1,1,1)}.$$ This can be calculated by the formula $$S_lambda cdot S_{(1)} = sum_{mu} S_{mu}$$ where $mu$ ranges over all partitions obtained from $lambda$ by adding a single box. (Pieri's formula)






              share|cite|improve this answer









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                3












                3








                3





                $begingroup$

                That formula is not correct. The correct decomposition is $$S_{(1)}^4 = S_{(4)} + 3 S_{(3,1)} + 2 S_{(2,2)} + 3 S_{(2,1,1)} + S_{(1,1,1,1)}.$$ This can be calculated by the formula $$S_lambda cdot S_{(1)} = sum_{mu} S_{mu}$$ where $mu$ ranges over all partitions obtained from $lambda$ by adding a single box. (Pieri's formula)






                share|cite|improve this answer









                $endgroup$



                That formula is not correct. The correct decomposition is $$S_{(1)}^4 = S_{(4)} + 3 S_{(3,1)} + 2 S_{(2,2)} + 3 S_{(2,1,1)} + S_{(1,1,1,1)}.$$ This can be calculated by the formula $$S_lambda cdot S_{(1)} = sum_{mu} S_{mu}$$ where $mu$ ranges over all partitions obtained from $lambda$ by adding a single box. (Pieri's formula)







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Aug 12 '15 at 7:52









                TedTed

                21.5k13260




                21.5k13260






























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