Counterexample for $f$ is strictly increasing ,$ g$ and $fcirc g$ is continous but f is not continous
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I wanted to find counterexample
Counterexample for $f$ is strictly increasing,$ g$ and $fcirc g$ is continuous but $f$ is not continuous
Where f and g are function form $[0,1]to [0,1]$
How to approach to find such example
Any Help will be appreciated
real-analysis examples-counterexamples
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add a comment |
$begingroup$
I wanted to find counterexample
Counterexample for $f$ is strictly increasing,$ g$ and $fcirc g$ is continuous but $f$ is not continuous
Where f and g are function form $[0,1]to [0,1]$
How to approach to find such example
Any Help will be appreciated
real-analysis examples-counterexamples
$endgroup$
add a comment |
$begingroup$
I wanted to find counterexample
Counterexample for $f$ is strictly increasing,$ g$ and $fcirc g$ is continuous but $f$ is not continuous
Where f and g are function form $[0,1]to [0,1]$
How to approach to find such example
Any Help will be appreciated
real-analysis examples-counterexamples
$endgroup$
I wanted to find counterexample
Counterexample for $f$ is strictly increasing,$ g$ and $fcirc g$ is continuous but $f$ is not continuous
Where f and g are function form $[0,1]to [0,1]$
How to approach to find such example
Any Help will be appreciated
real-analysis examples-counterexamples
real-analysis examples-counterexamples
asked Dec 2 '18 at 9:24
MathLoverMathLover
49710
49710
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1 Answer
1
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oldest
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Hint: Let $g(x)=0{}{}{}{}{}{}$.
$endgroup$
$begingroup$
great Sir...I am always missing such examples...
$endgroup$
– MathLover
Dec 2 '18 at 9:29
$begingroup$
But Sir If We want both map as surjective map then is it possible to such construct map?
$endgroup$
– MathLover
Dec 2 '18 at 9:31
2
$begingroup$
@MathLover No, if $g$ is surjective and continuous, and $f$ is not continuous, then for some $x_0$, we will have $g(x_0)$ be some point of discontinuity of $f$, which means that $f(g(x))$ must be discontinuous at that point. I've glossed over a few details here, but that's the general argument.
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– Arthur
Dec 2 '18 at 9:36
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
Hint: Let $g(x)=0{}{}{}{}{}{}$.
$endgroup$
$begingroup$
great Sir...I am always missing such examples...
$endgroup$
– MathLover
Dec 2 '18 at 9:29
$begingroup$
But Sir If We want both map as surjective map then is it possible to such construct map?
$endgroup$
– MathLover
Dec 2 '18 at 9:31
2
$begingroup$
@MathLover No, if $g$ is surjective and continuous, and $f$ is not continuous, then for some $x_0$, we will have $g(x_0)$ be some point of discontinuity of $f$, which means that $f(g(x))$ must be discontinuous at that point. I've glossed over a few details here, but that's the general argument.
$endgroup$
– Arthur
Dec 2 '18 at 9:36
add a comment |
$begingroup$
Hint: Let $g(x)=0{}{}{}{}{}{}$.
$endgroup$
$begingroup$
great Sir...I am always missing such examples...
$endgroup$
– MathLover
Dec 2 '18 at 9:29
$begingroup$
But Sir If We want both map as surjective map then is it possible to such construct map?
$endgroup$
– MathLover
Dec 2 '18 at 9:31
2
$begingroup$
@MathLover No, if $g$ is surjective and continuous, and $f$ is not continuous, then for some $x_0$, we will have $g(x_0)$ be some point of discontinuity of $f$, which means that $f(g(x))$ must be discontinuous at that point. I've glossed over a few details here, but that's the general argument.
$endgroup$
– Arthur
Dec 2 '18 at 9:36
add a comment |
$begingroup$
Hint: Let $g(x)=0{}{}{}{}{}{}$.
$endgroup$
Hint: Let $g(x)=0{}{}{}{}{}{}$.
answered Dec 2 '18 at 9:28
ArthurArthur
113k7110193
113k7110193
$begingroup$
great Sir...I am always missing such examples...
$endgroup$
– MathLover
Dec 2 '18 at 9:29
$begingroup$
But Sir If We want both map as surjective map then is it possible to such construct map?
$endgroup$
– MathLover
Dec 2 '18 at 9:31
2
$begingroup$
@MathLover No, if $g$ is surjective and continuous, and $f$ is not continuous, then for some $x_0$, we will have $g(x_0)$ be some point of discontinuity of $f$, which means that $f(g(x))$ must be discontinuous at that point. I've glossed over a few details here, but that's the general argument.
$endgroup$
– Arthur
Dec 2 '18 at 9:36
add a comment |
$begingroup$
great Sir...I am always missing such examples...
$endgroup$
– MathLover
Dec 2 '18 at 9:29
$begingroup$
But Sir If We want both map as surjective map then is it possible to such construct map?
$endgroup$
– MathLover
Dec 2 '18 at 9:31
2
$begingroup$
@MathLover No, if $g$ is surjective and continuous, and $f$ is not continuous, then for some $x_0$, we will have $g(x_0)$ be some point of discontinuity of $f$, which means that $f(g(x))$ must be discontinuous at that point. I've glossed over a few details here, but that's the general argument.
$endgroup$
– Arthur
Dec 2 '18 at 9:36
$begingroup$
great Sir...I am always missing such examples...
$endgroup$
– MathLover
Dec 2 '18 at 9:29
$begingroup$
great Sir...I am always missing such examples...
$endgroup$
– MathLover
Dec 2 '18 at 9:29
$begingroup$
But Sir If We want both map as surjective map then is it possible to such construct map?
$endgroup$
– MathLover
Dec 2 '18 at 9:31
$begingroup$
But Sir If We want both map as surjective map then is it possible to such construct map?
$endgroup$
– MathLover
Dec 2 '18 at 9:31
2
2
$begingroup$
@MathLover No, if $g$ is surjective and continuous, and $f$ is not continuous, then for some $x_0$, we will have $g(x_0)$ be some point of discontinuity of $f$, which means that $f(g(x))$ must be discontinuous at that point. I've glossed over a few details here, but that's the general argument.
$endgroup$
– Arthur
Dec 2 '18 at 9:36
$begingroup$
@MathLover No, if $g$ is surjective and continuous, and $f$ is not continuous, then for some $x_0$, we will have $g(x_0)$ be some point of discontinuity of $f$, which means that $f(g(x))$ must be discontinuous at that point. I've glossed over a few details here, but that's the general argument.
$endgroup$
– Arthur
Dec 2 '18 at 9:36
add a comment |
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