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
general-topology
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up vote
2
down vote
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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
general-topology
add a comment |Â
up vote
2
down vote
favorite
up vote
2
down vote
favorite
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
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
general-topology
edited Sep 7 at 2:15
asked Sep 7 at 1:52
Non-Archimedean
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165
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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
1
active
oldest
votes
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 $C.$
add a comment |Â
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 $C.$
add a comment |Â
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 $C.$
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 $C.$
answered Sep 7 at 3:01
DanielWainfleet
32.3k31644
32.3k31644
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