Complement space of a finite dimensional space over a finite field












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Let $V$ be a finite dimensional space over the field $mathbb{F}_q$ of $q$ elements and let $Usubset V$ a subspace of $V$. How many subspaces $Wsubset V$ are there such that $Wcap U = 0 $ and $V=W+U$ ?



I've been trying to use Jordan canonical form but I think I'm missing something here, I just can't get it :(










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    Let $V$ be a finite dimensional space over the field $mathbb{F}_q$ of $q$ elements and let $Usubset V$ a subspace of $V$. How many subspaces $Wsubset V$ are there such that $Wcap U = 0 $ and $V=W+U$ ?



    I've been trying to use Jordan canonical form but I think I'm missing something here, I just can't get it :(










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      0





      $begingroup$


      Let $V$ be a finite dimensional space over the field $mathbb{F}_q$ of $q$ elements and let $Usubset V$ a subspace of $V$. How many subspaces $Wsubset V$ are there such that $Wcap U = 0 $ and $V=W+U$ ?



      I've been trying to use Jordan canonical form but I think I'm missing something here, I just can't get it :(










      share|cite|improve this question









      $endgroup$




      Let $V$ be a finite dimensional space over the field $mathbb{F}_q$ of $q$ elements and let $Usubset V$ a subspace of $V$. How many subspaces $Wsubset V$ are there such that $Wcap U = 0 $ and $V=W+U$ ?



      I've been trying to use Jordan canonical form but I think I'm missing something here, I just can't get it :(







      linear-algebra finite-groups modules finite-fields jordan-normal-form






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      asked Jan 6 at 10:15









      Diego Andrés Jauré RomeroDiego Andrés Jauré Romero

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          $begingroup$

          Hint: count the number of ways that a given basis of $U$ can be completed into a basis of $V$, and divide by the number of bases of any fitting $W$.






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            1 Answer
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            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            2












            $begingroup$

            Hint: count the number of ways that a given basis of $U$ can be completed into a basis of $V$, and divide by the number of bases of any fitting $W$.






            share|cite|improve this answer









            $endgroup$


















              2












              $begingroup$

              Hint: count the number of ways that a given basis of $U$ can be completed into a basis of $V$, and divide by the number of bases of any fitting $W$.






              share|cite|improve this answer









              $endgroup$
















                2












                2








                2





                $begingroup$

                Hint: count the number of ways that a given basis of $U$ can be completed into a basis of $V$, and divide by the number of bases of any fitting $W$.






                share|cite|improve this answer









                $endgroup$



                Hint: count the number of ways that a given basis of $U$ can be completed into a basis of $V$, and divide by the number of bases of any fitting $W$.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Jan 6 at 10:30









                MindlackMindlack

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