Why does not the Montel Theorem apply in this case?












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enter image description here



I have proved that the family is not equicontinuous, but it is not understanding why the theorem 3.3 can not be applied. Can someone explain me?










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  • 2




    Probably because $sin(nx)$ is not holomorphic.
    – Lukas Kofler
    Nov 29 at 12:55
















-1














enter image description here



I have proved that the family is not equicontinuous, but it is not understanding why the theorem 3.3 can not be applied. Can someone explain me?










share|cite|improve this question


















  • 2




    Probably because $sin(nx)$ is not holomorphic.
    – Lukas Kofler
    Nov 29 at 12:55














-1












-1








-1







enter image description here



I have proved that the family is not equicontinuous, but it is not understanding why the theorem 3.3 can not be applied. Can someone explain me?










share|cite|improve this question













enter image description here



I have proved that the family is not equicontinuous, but it is not understanding why the theorem 3.3 can not be applied. Can someone explain me?







complex-analysis






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asked Nov 29 at 12:53









Ricardo Freire

392110




392110








  • 2




    Probably because $sin(nx)$ is not holomorphic.
    – Lukas Kofler
    Nov 29 at 12:55














  • 2




    Probably because $sin(nx)$ is not holomorphic.
    – Lukas Kofler
    Nov 29 at 12:55








2




2




Probably because $sin(nx)$ is not holomorphic.
– Lukas Kofler
Nov 29 at 12:55




Probably because $sin(nx)$ is not holomorphic.
– Lukas Kofler
Nov 29 at 12:55










1 Answer
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This is because if we take any open set $A$ in the complex plane such that $(0,1)subset A$ then $A$ must have an element $z=a+bi$ with $bneq 0.$
Therefore $|sin nz|=|(2i)^{-1} (e^{nia -nb} -e^{-nia +nb})|to infty $ as $nto infty.$
So the family is not uniformly bounded in any region $A$ in complex plane, such that $(0,1)subset A.$






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  • The book itself says that the family is uniformly limited, do not you think it can be something else? Being uniformly limited does not refer to the open containing the set, but to the compacts that are contained in the set.
    – Ricardo Freire
    Nov 29 at 13:37






  • 1




    In the theorem $Omega$ is an open subset of the plane. If $Omega$ is an open subset of the plane and $(0,1)subsetOmega$ then there exists a compact $Ksubset Omega$ such that $\sin(nz)$ is not uniformly bounded on $K$. That's clear from the above, since singletons are compact.
    – David C. Ullrich
    Nov 29 at 15:08













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This is because if we take any open set $A$ in the complex plane such that $(0,1)subset A$ then $A$ must have an element $z=a+bi$ with $bneq 0.$
Therefore $|sin nz|=|(2i)^{-1} (e^{nia -nb} -e^{-nia +nb})|to infty $ as $nto infty.$
So the family is not uniformly bounded in any region $A$ in complex plane, such that $(0,1)subset A.$






share|cite|improve this answer





















  • The book itself says that the family is uniformly limited, do not you think it can be something else? Being uniformly limited does not refer to the open containing the set, but to the compacts that are contained in the set.
    – Ricardo Freire
    Nov 29 at 13:37






  • 1




    In the theorem $Omega$ is an open subset of the plane. If $Omega$ is an open subset of the plane and $(0,1)subsetOmega$ then there exists a compact $Ksubset Omega$ such that $\sin(nz)$ is not uniformly bounded on $K$. That's clear from the above, since singletons are compact.
    – David C. Ullrich
    Nov 29 at 15:08


















1














This is because if we take any open set $A$ in the complex plane such that $(0,1)subset A$ then $A$ must have an element $z=a+bi$ with $bneq 0.$
Therefore $|sin nz|=|(2i)^{-1} (e^{nia -nb} -e^{-nia +nb})|to infty $ as $nto infty.$
So the family is not uniformly bounded in any region $A$ in complex plane, such that $(0,1)subset A.$






share|cite|improve this answer





















  • The book itself says that the family is uniformly limited, do not you think it can be something else? Being uniformly limited does not refer to the open containing the set, but to the compacts that are contained in the set.
    – Ricardo Freire
    Nov 29 at 13:37






  • 1




    In the theorem $Omega$ is an open subset of the plane. If $Omega$ is an open subset of the plane and $(0,1)subsetOmega$ then there exists a compact $Ksubset Omega$ such that $\sin(nz)$ is not uniformly bounded on $K$. That's clear from the above, since singletons are compact.
    – David C. Ullrich
    Nov 29 at 15:08
















1












1








1






This is because if we take any open set $A$ in the complex plane such that $(0,1)subset A$ then $A$ must have an element $z=a+bi$ with $bneq 0.$
Therefore $|sin nz|=|(2i)^{-1} (e^{nia -nb} -e^{-nia +nb})|to infty $ as $nto infty.$
So the family is not uniformly bounded in any region $A$ in complex plane, such that $(0,1)subset A.$






share|cite|improve this answer












This is because if we take any open set $A$ in the complex plane such that $(0,1)subset A$ then $A$ must have an element $z=a+bi$ with $bneq 0.$
Therefore $|sin nz|=|(2i)^{-1} (e^{nia -nb} -e^{-nia +nb})|to infty $ as $nto infty.$
So the family is not uniformly bounded in any region $A$ in complex plane, such that $(0,1)subset A.$







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answered Nov 29 at 13:11









MotylaNogaTomkaMazura

6,564917




6,564917












  • The book itself says that the family is uniformly limited, do not you think it can be something else? Being uniformly limited does not refer to the open containing the set, but to the compacts that are contained in the set.
    – Ricardo Freire
    Nov 29 at 13:37






  • 1




    In the theorem $Omega$ is an open subset of the plane. If $Omega$ is an open subset of the plane and $(0,1)subsetOmega$ then there exists a compact $Ksubset Omega$ such that $\sin(nz)$ is not uniformly bounded on $K$. That's clear from the above, since singletons are compact.
    – David C. Ullrich
    Nov 29 at 15:08




















  • The book itself says that the family is uniformly limited, do not you think it can be something else? Being uniformly limited does not refer to the open containing the set, but to the compacts that are contained in the set.
    – Ricardo Freire
    Nov 29 at 13:37






  • 1




    In the theorem $Omega$ is an open subset of the plane. If $Omega$ is an open subset of the plane and $(0,1)subsetOmega$ then there exists a compact $Ksubset Omega$ such that $\sin(nz)$ is not uniformly bounded on $K$. That's clear from the above, since singletons are compact.
    – David C. Ullrich
    Nov 29 at 15:08


















The book itself says that the family is uniformly limited, do not you think it can be something else? Being uniformly limited does not refer to the open containing the set, but to the compacts that are contained in the set.
– Ricardo Freire
Nov 29 at 13:37




The book itself says that the family is uniformly limited, do not you think it can be something else? Being uniformly limited does not refer to the open containing the set, but to the compacts that are contained in the set.
– Ricardo Freire
Nov 29 at 13:37




1




1




In the theorem $Omega$ is an open subset of the plane. If $Omega$ is an open subset of the plane and $(0,1)subsetOmega$ then there exists a compact $Ksubset Omega$ such that $\sin(nz)$ is not uniformly bounded on $K$. That's clear from the above, since singletons are compact.
– David C. Ullrich
Nov 29 at 15:08






In the theorem $Omega$ is an open subset of the plane. If $Omega$ is an open subset of the plane and $(0,1)subsetOmega$ then there exists a compact $Ksubset Omega$ such that $\sin(nz)$ is not uniformly bounded on $K$. That's clear from the above, since singletons are compact.
– David C. Ullrich
Nov 29 at 15:08




















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