how do we prove that a sum of two periods is still a period?optimizing Frobenius instance solutionsDoes “all points rational” imply “constant” for this “cubic” curve over an arbitrary field?What is the relationship between these two notions of “period”?Computer software for periodsIs special value of Epstein zeta function in 3 variables a period?Property of a derivative in global fieldWhy are Green functions involved in intersection theory?Waldspurger Formula as a Torus IntegralHow does $zeta^mathfrakm(2)$ and relate to $zeta(2)$?Is there an algorithm for numerical approximation of (naive) period integrals

how do we prove that a sum of two periods is still a period?


optimizing Frobenius instance solutionsDoes “all points rational” imply “constant” for this “cubic” curve over an arbitrary field?What is the relationship between these two notions of “period”?Computer software for periodsIs special value of Epstein zeta function in 3 variables a period?Property of a derivative in global fieldWhy are Green functions involved in intersection theory?Waldspurger Formula as a Torus IntegralHow does $zeta^mathfrakm(2)$ and relate to $zeta(2)$?Is there an algorithm for numerical approximation of (naive) period integrals













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Kontsevich and Zagier define periods as the values of absolutely convergent integrals $int_sigma f$ where $f$ is a rational function with rational coefficients and $sigma$ is a semi-algebraic subset of $mathbbR^n$. How do we prove that the sum of two such numbers is still of this form? I've tried a few things but they don't seem to work...










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    8












    $begingroup$


    Kontsevich and Zagier define periods as the values of absolutely convergent integrals $int_sigma f$ where $f$ is a rational function with rational coefficients and $sigma$ is a semi-algebraic subset of $mathbbR^n$. How do we prove that the sum of two such numbers is still of this form? I've tried a few things but they don't seem to work...










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      8


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      $begingroup$


      Kontsevich and Zagier define periods as the values of absolutely convergent integrals $int_sigma f$ where $f$ is a rational function with rational coefficients and $sigma$ is a semi-algebraic subset of $mathbbR^n$. How do we prove that the sum of two such numbers is still of this form? I've tried a few things but they don't seem to work...










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      Check out our Code of Conduct.







      $endgroup$




      Kontsevich and Zagier define periods as the values of absolutely convergent integrals $int_sigma f$ where $f$ is a rational function with rational coefficients and $sigma$ is a semi-algebraic subset of $mathbbR^n$. How do we prove that the sum of two such numbers is still of this form? I've tried a few things but they don't seem to work...







      ag.algebraic-geometry nt.number-theory






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      asked 4 hours ago









      periodsperiods

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          Let $alpha$ and $beta$ be two periods corresponding respectively to two absolutely convergent integrals $int_sigma f(x)dx$ and $int_tau g(y)dy$, where $f$ (resp. $g$) is a rational function on $Bbb Q$ with $r$ (resp. $s$) variables and $sigma$ (resp. $tau$) is a semi-algebraic subset of $Bbb R^r$ (resp. $Bbb R^s$).



          Setting $omega:=sigmatimesleftlbrace0rightrbracetimes(0,1)^scoprod(0,1)^rtimesleftlbrace1rightrbracetimestau$, one immediately gets that $$alpha+beta=int_omega left[(1-t)f(x)+tg(y)right]dxdydt$$which is again an absolutely convergent integral, so that $alpha+beta$ is a period.






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            13












            $begingroup$

            Let $alpha$ and $beta$ be two periods corresponding respectively to two absolutely convergent integrals $int_sigma f(x)dx$ and $int_tau g(y)dy$, where $f$ (resp. $g$) is a rational function on $Bbb Q$ with $r$ (resp. $s$) variables and $sigma$ (resp. $tau$) is a semi-algebraic subset of $Bbb R^r$ (resp. $Bbb R^s$).



            Setting $omega:=sigmatimesleftlbrace0rightrbracetimes(0,1)^scoprod(0,1)^rtimesleftlbrace1rightrbracetimestau$, one immediately gets that $$alpha+beta=int_omega left[(1-t)f(x)+tg(y)right]dxdydt$$which is again an absolutely convergent integral, so that $alpha+beta$ is a period.






            share|cite|improve this answer









            $endgroup$

















              13












              $begingroup$

              Let $alpha$ and $beta$ be two periods corresponding respectively to two absolutely convergent integrals $int_sigma f(x)dx$ and $int_tau g(y)dy$, where $f$ (resp. $g$) is a rational function on $Bbb Q$ with $r$ (resp. $s$) variables and $sigma$ (resp. $tau$) is a semi-algebraic subset of $Bbb R^r$ (resp. $Bbb R^s$).



              Setting $omega:=sigmatimesleftlbrace0rightrbracetimes(0,1)^scoprod(0,1)^rtimesleftlbrace1rightrbracetimestau$, one immediately gets that $$alpha+beta=int_omega left[(1-t)f(x)+tg(y)right]dxdydt$$which is again an absolutely convergent integral, so that $alpha+beta$ is a period.






              share|cite|improve this answer









              $endgroup$















                13












                13








                13





                $begingroup$

                Let $alpha$ and $beta$ be two periods corresponding respectively to two absolutely convergent integrals $int_sigma f(x)dx$ and $int_tau g(y)dy$, where $f$ (resp. $g$) is a rational function on $Bbb Q$ with $r$ (resp. $s$) variables and $sigma$ (resp. $tau$) is a semi-algebraic subset of $Bbb R^r$ (resp. $Bbb R^s$).



                Setting $omega:=sigmatimesleftlbrace0rightrbracetimes(0,1)^scoprod(0,1)^rtimesleftlbrace1rightrbracetimestau$, one immediately gets that $$alpha+beta=int_omega left[(1-t)f(x)+tg(y)right]dxdydt$$which is again an absolutely convergent integral, so that $alpha+beta$ is a period.






                share|cite|improve this answer









                $endgroup$



                Let $alpha$ and $beta$ be two periods corresponding respectively to two absolutely convergent integrals $int_sigma f(x)dx$ and $int_tau g(y)dy$, where $f$ (resp. $g$) is a rational function on $Bbb Q$ with $r$ (resp. $s$) variables and $sigma$ (resp. $tau$) is a semi-algebraic subset of $Bbb R^r$ (resp. $Bbb R^s$).



                Setting $omega:=sigmatimesleftlbrace0rightrbracetimes(0,1)^scoprod(0,1)^rtimesleftlbrace1rightrbracetimestau$, one immediately gets that $$alpha+beta=int_omega left[(1-t)f(x)+tg(y)right]dxdydt$$which is again an absolutely convergent integral, so that $alpha+beta$ is a period.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered 3 hours ago









                GaussianGaussian

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