The derivative of the flow is a homothecy












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$begingroup$


Let $a,b in mathbb{R}^n.$



$Φ_{a,t} (x) = a + (x − a)e^t$ is the flow corresponding to the vector field $X(x) = x-a$.



Calculate $Z(x, t) = (T_x Φ_{a,t} )^{−1} (X_b (Φ_{a,t} (x)))$.



I don't understand the solution, it states that:



$T_x Φ_{a,t}$ is the homothecy of ratio $e^{-t}$. Why is that? I know that $Φ_{a,t}$ is the homothecy of ratio $e^{-t}$ and center $a$ but I can't go further.



Thank you for your help.










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$endgroup$

















    0












    $begingroup$


    Let $a,b in mathbb{R}^n.$



    $Φ_{a,t} (x) = a + (x − a)e^t$ is the flow corresponding to the vector field $X(x) = x-a$.



    Calculate $Z(x, t) = (T_x Φ_{a,t} )^{−1} (X_b (Φ_{a,t} (x)))$.



    I don't understand the solution, it states that:



    $T_x Φ_{a,t}$ is the homothecy of ratio $e^{-t}$. Why is that? I know that $Φ_{a,t}$ is the homothecy of ratio $e^{-t}$ and center $a$ but I can't go further.



    Thank you for your help.










    share|cite|improve this question









    $endgroup$















      0












      0








      0





      $begingroup$


      Let $a,b in mathbb{R}^n.$



      $Φ_{a,t} (x) = a + (x − a)e^t$ is the flow corresponding to the vector field $X(x) = x-a$.



      Calculate $Z(x, t) = (T_x Φ_{a,t} )^{−1} (X_b (Φ_{a,t} (x)))$.



      I don't understand the solution, it states that:



      $T_x Φ_{a,t}$ is the homothecy of ratio $e^{-t}$. Why is that? I know that $Φ_{a,t}$ is the homothecy of ratio $e^{-t}$ and center $a$ but I can't go further.



      Thank you for your help.










      share|cite|improve this question









      $endgroup$




      Let $a,b in mathbb{R}^n.$



      $Φ_{a,t} (x) = a + (x − a)e^t$ is the flow corresponding to the vector field $X(x) = x-a$.



      Calculate $Z(x, t) = (T_x Φ_{a,t} )^{−1} (X_b (Φ_{a,t} (x)))$.



      I don't understand the solution, it states that:



      $T_x Φ_{a,t}$ is the homothecy of ratio $e^{-t}$. Why is that? I know that $Φ_{a,t}$ is the homothecy of ratio $e^{-t}$ and center $a$ but I can't go further.



      Thank you for your help.







      differential-geometry vector-fields






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      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked Jan 7 at 19:04









      PerelManPerelMan

      760414




      760414






















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