compare these two topologies $ tau_1, tau_2$.

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Let us denote $ V$ to be the set of all real valued functions $ f: mathbbR to mathbbR $. Consider the two Topologies $ tau_1 , tau_2 $ on $ V$ as follows:



$tau_1=$ induced by uniform convergence on compact sets



$tau_2=$induced by local neighborhoods $$ N(f,[a,b], epsilon)=g : $$



Then compare these two topologies $ tau_1, tau_2$.



Are they same?



Answer:



The topology $ tau_1$ induced by uniform convergence while the topology. So it has base $ g(x)-f(x)<epsilon $



which is same as $ tau_2$.



Thus $ tau_1, tau_2$ are same topology .



Am I right ?



Help me doing this










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    up vote
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    down vote

    favorite
    1












    Let us denote $ V$ to be the set of all real valued functions $ f: mathbbR to mathbbR $. Consider the two Topologies $ tau_1 , tau_2 $ on $ V$ as follows:



    $tau_1=$ induced by uniform convergence on compact sets



    $tau_2=$induced by local neighborhoods $$ N(f,[a,b], epsilon)=g : $$



    Then compare these two topologies $ tau_1, tau_2$.



    Are they same?



    Answer:



    The topology $ tau_1$ induced by uniform convergence while the topology. So it has base $ g(x)-f(x)<epsilon $



    which is same as $ tau_2$.



    Thus $ tau_1, tau_2$ are same topology .



    Am I right ?



    Help me doing this










    share|cite|improve this question

























      up vote
      2
      down vote

      favorite
      1









      up vote
      2
      down vote

      favorite
      1






      1





      Let us denote $ V$ to be the set of all real valued functions $ f: mathbbR to mathbbR $. Consider the two Topologies $ tau_1 , tau_2 $ on $ V$ as follows:



      $tau_1=$ induced by uniform convergence on compact sets



      $tau_2=$induced by local neighborhoods $$ N(f,[a,b], epsilon)=g : $$



      Then compare these two topologies $ tau_1, tau_2$.



      Are they same?



      Answer:



      The topology $ tau_1$ induced by uniform convergence while the topology. So it has base $ g(x)-f(x)<epsilon $



      which is same as $ tau_2$.



      Thus $ tau_1, tau_2$ are same topology .



      Am I right ?



      Help me doing this










      share|cite|improve this question















      Let us denote $ V$ to be the set of all real valued functions $ f: mathbbR to mathbbR $. Consider the two Topologies $ tau_1 , tau_2 $ on $ V$ as follows:



      $tau_1=$ induced by uniform convergence on compact sets



      $tau_2=$induced by local neighborhoods $$ N(f,[a,b], epsilon)=g : $$



      Then compare these two topologies $ tau_1, tau_2$.



      Are they same?



      Answer:



      The topology $ tau_1$ induced by uniform convergence while the topology. So it has base $ g(x)-f(x)<epsilon $



      which is same as $ tau_2$.



      Thus $ tau_1, tau_2$ are same topology .



      Am I right ?



      Help me doing this







      general-topology






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      edited Sep 7 at 2:15

























      asked Sep 7 at 1:52









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          1 Answer
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          You are right.



          (i). If a sequence $(f_n)_n$ converges uniformly to $f$ on every compact subset of $Bbb R$, it will, a fortiori, converge uniformly to $f$ on every compact (i.e. closed bounded) interval.



          (ii). If $(f_n)_n$ converges uniformly to $f$ on every compact interval, and if $C$ is any compact subset of $Bbb R,$ then there exist $a,bin Bbb R$ with $[a,b]supset C.$ Now $(f_n)_n$ converges uniformly to $f$ on $[a,b],$ so $(f_n)_n$ converges uniformly to $f$ on any subset of $[a,b].$ In particular, $(f_n)_n$ converges uniformly to $f$ on $C.$






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            1 Answer
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            active

            oldest

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            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes








            up vote
            2
            down vote



            accepted










            You are right.



            (i). If a sequence $(f_n)_n$ converges uniformly to $f$ on every compact subset of $Bbb R$, it will, a fortiori, converge uniformly to $f$ on every compact (i.e. closed bounded) interval.



            (ii). If $(f_n)_n$ converges uniformly to $f$ on every compact interval, and if $C$ is any compact subset of $Bbb R,$ then there exist $a,bin Bbb R$ with $[a,b]supset C.$ Now $(f_n)_n$ converges uniformly to $f$ on $[a,b],$ so $(f_n)_n$ converges uniformly to $f$ on any subset of $[a,b].$ In particular, $(f_n)_n$ converges uniformly to $f$ on $C.$






            share|cite|improve this answer
























              up vote
              2
              down vote



              accepted










              You are right.



              (i). If a sequence $(f_n)_n$ converges uniformly to $f$ on every compact subset of $Bbb R$, it will, a fortiori, converge uniformly to $f$ on every compact (i.e. closed bounded) interval.



              (ii). If $(f_n)_n$ converges uniformly to $f$ on every compact interval, and if $C$ is any compact subset of $Bbb R,$ then there exist $a,bin Bbb R$ with $[a,b]supset C.$ Now $(f_n)_n$ converges uniformly to $f$ on $[a,b],$ so $(f_n)_n$ converges uniformly to $f$ on any subset of $[a,b].$ In particular, $(f_n)_n$ converges uniformly to $f$ on $C.$






              share|cite|improve this answer






















                up vote
                2
                down vote



                accepted







                up vote
                2
                down vote



                accepted






                You are right.



                (i). If a sequence $(f_n)_n$ converges uniformly to $f$ on every compact subset of $Bbb R$, it will, a fortiori, converge uniformly to $f$ on every compact (i.e. closed bounded) interval.



                (ii). If $(f_n)_n$ converges uniformly to $f$ on every compact interval, and if $C$ is any compact subset of $Bbb R,$ then there exist $a,bin Bbb R$ with $[a,b]supset C.$ Now $(f_n)_n$ converges uniformly to $f$ on $[a,b],$ so $(f_n)_n$ converges uniformly to $f$ on any subset of $[a,b].$ In particular, $(f_n)_n$ converges uniformly to $f$ on $C.$






                share|cite|improve this answer












                You are right.



                (i). If a sequence $(f_n)_n$ converges uniformly to $f$ on every compact subset of $Bbb R$, it will, a fortiori, converge uniformly to $f$ on every compact (i.e. closed bounded) interval.



                (ii). If $(f_n)_n$ converges uniformly to $f$ on every compact interval, and if $C$ is any compact subset of $Bbb R,$ then there exist $a,bin Bbb R$ with $[a,b]supset C.$ Now $(f_n)_n$ converges uniformly to $f$ on $[a,b],$ so $(f_n)_n$ converges uniformly to $f$ on any subset of $[a,b].$ In particular, $(f_n)_n$ converges uniformly to $f$ on $C.$







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Sep 7 at 3:01









                DanielWainfleet

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