Exponential type of a product of entire functions











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Let ${a_n}_{n=1}^infty$ and ${b_m}_{m=1}^infty$ be two sequences of points in $mathbb{C}$ such that
$$
f(z)=prod_{n=1}^inftyleft(1-frac{z}{a_n}right)quadmbox{and}quad g(z)=prod_{m=1}^inftyleft(1-frac{z}{b_m}right)
$$

are entire functions of finite exponential types $0<A_f<infty$ and $0<A_g<infty$ (growth orders are $rho_f=rho_g=1$), respectively. Is it true that the exponential type $A_{fg}$ of the entire function $f(z)g(z)$ satisfies
$$
max{A_f,A_g}<A_{fg}
$$

(strict inequality)?



More generally, given that the growth of $f$ as above is $rho_f=1$, is there a way to establish the exponential type from the sequence ${a_n}$?



Thank you.



Edit: Question answered on mathoverflow here.










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    up vote
    1
    down vote

    favorite












    Let ${a_n}_{n=1}^infty$ and ${b_m}_{m=1}^infty$ be two sequences of points in $mathbb{C}$ such that
    $$
    f(z)=prod_{n=1}^inftyleft(1-frac{z}{a_n}right)quadmbox{and}quad g(z)=prod_{m=1}^inftyleft(1-frac{z}{b_m}right)
    $$

    are entire functions of finite exponential types $0<A_f<infty$ and $0<A_g<infty$ (growth orders are $rho_f=rho_g=1$), respectively. Is it true that the exponential type $A_{fg}$ of the entire function $f(z)g(z)$ satisfies
    $$
    max{A_f,A_g}<A_{fg}
    $$

    (strict inequality)?



    More generally, given that the growth of $f$ as above is $rho_f=1$, is there a way to establish the exponential type from the sequence ${a_n}$?



    Thank you.



    Edit: Question answered on mathoverflow here.










    share|cite|improve this question


























      up vote
      1
      down vote

      favorite









      up vote
      1
      down vote

      favorite











      Let ${a_n}_{n=1}^infty$ and ${b_m}_{m=1}^infty$ be two sequences of points in $mathbb{C}$ such that
      $$
      f(z)=prod_{n=1}^inftyleft(1-frac{z}{a_n}right)quadmbox{and}quad g(z)=prod_{m=1}^inftyleft(1-frac{z}{b_m}right)
      $$

      are entire functions of finite exponential types $0<A_f<infty$ and $0<A_g<infty$ (growth orders are $rho_f=rho_g=1$), respectively. Is it true that the exponential type $A_{fg}$ of the entire function $f(z)g(z)$ satisfies
      $$
      max{A_f,A_g}<A_{fg}
      $$

      (strict inequality)?



      More generally, given that the growth of $f$ as above is $rho_f=1$, is there a way to establish the exponential type from the sequence ${a_n}$?



      Thank you.



      Edit: Question answered on mathoverflow here.










      share|cite|improve this question















      Let ${a_n}_{n=1}^infty$ and ${b_m}_{m=1}^infty$ be two sequences of points in $mathbb{C}$ such that
      $$
      f(z)=prod_{n=1}^inftyleft(1-frac{z}{a_n}right)quadmbox{and}quad g(z)=prod_{m=1}^inftyleft(1-frac{z}{b_m}right)
      $$

      are entire functions of finite exponential types $0<A_f<infty$ and $0<A_g<infty$ (growth orders are $rho_f=rho_g=1$), respectively. Is it true that the exponential type $A_{fg}$ of the entire function $f(z)g(z)$ satisfies
      $$
      max{A_f,A_g}<A_{fg}
      $$

      (strict inequality)?



      More generally, given that the growth of $f$ as above is $rho_f=1$, is there a way to establish the exponential type from the sequence ${a_n}$?



      Thank you.



      Edit: Question answered on mathoverflow here.







      complex-analysis






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      edited Nov 29 at 22:16

























      asked Nov 27 at 20:07









      Bedovlat

      591311




      591311



























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