Is the projection from $mathbb R^n$ locally isometric to the flat torus?












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I’m reading a problem asking to introduce a Riemannian metric on $T^n$ in such a way that the projection $pi(x_1,...,x_n)=(exp(ix_1),...,exp(ix_n))$ from $mathbb R^n$ to $T^n$ is a local isometry. Does the flat metric apply here?



By definition, flat torus is defined as the product of n copies of the Riemannian manifold $S^1$ with its metric induced by $mathbb R$.










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  • $begingroup$
    Maybe you ought to clarify what the projection $pi$ you refer to is?
    $endgroup$
    – T_M
    Dec 13 '18 at 15:16












  • $begingroup$
    I editted my question @T_M
    $endgroup$
    – User12239
    Dec 13 '18 at 15:19










  • $begingroup$
    isn't the flat metric exactly defined via this property? related to this: math.stackexchange.com/questions/450110/…
    $endgroup$
    – Balou
    Dec 13 '18 at 15:19










  • $begingroup$
    I’m reading DoCarmo’s book and the definition there is different @Balou
    $endgroup$
    – User12239
    Dec 13 '18 at 15:23










  • $begingroup$
    maybe you should state then how "the flat metric" is defined in DoCarmo
    $endgroup$
    – Balou
    Dec 13 '18 at 15:29
















0












$begingroup$


I’m reading a problem asking to introduce a Riemannian metric on $T^n$ in such a way that the projection $pi(x_1,...,x_n)=(exp(ix_1),...,exp(ix_n))$ from $mathbb R^n$ to $T^n$ is a local isometry. Does the flat metric apply here?



By definition, flat torus is defined as the product of n copies of the Riemannian manifold $S^1$ with its metric induced by $mathbb R$.










share|cite|improve this question











$endgroup$












  • $begingroup$
    Maybe you ought to clarify what the projection $pi$ you refer to is?
    $endgroup$
    – T_M
    Dec 13 '18 at 15:16












  • $begingroup$
    I editted my question @T_M
    $endgroup$
    – User12239
    Dec 13 '18 at 15:19










  • $begingroup$
    isn't the flat metric exactly defined via this property? related to this: math.stackexchange.com/questions/450110/…
    $endgroup$
    – Balou
    Dec 13 '18 at 15:19










  • $begingroup$
    I’m reading DoCarmo’s book and the definition there is different @Balou
    $endgroup$
    – User12239
    Dec 13 '18 at 15:23










  • $begingroup$
    maybe you should state then how "the flat metric" is defined in DoCarmo
    $endgroup$
    – Balou
    Dec 13 '18 at 15:29














0












0








0





$begingroup$


I’m reading a problem asking to introduce a Riemannian metric on $T^n$ in such a way that the projection $pi(x_1,...,x_n)=(exp(ix_1),...,exp(ix_n))$ from $mathbb R^n$ to $T^n$ is a local isometry. Does the flat metric apply here?



By definition, flat torus is defined as the product of n copies of the Riemannian manifold $S^1$ with its metric induced by $mathbb R$.










share|cite|improve this question











$endgroup$




I’m reading a problem asking to introduce a Riemannian metric on $T^n$ in such a way that the projection $pi(x_1,...,x_n)=(exp(ix_1),...,exp(ix_n))$ from $mathbb R^n$ to $T^n$ is a local isometry. Does the flat metric apply here?



By definition, flat torus is defined as the product of n copies of the Riemannian manifold $S^1$ with its metric induced by $mathbb R$.







differential-geometry riemannian-geometry smooth-manifolds






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share|cite|improve this question













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share|cite|improve this question








edited Dec 13 '18 at 15:38







User12239

















asked Dec 13 '18 at 15:12









User12239User12239

453216




453216












  • $begingroup$
    Maybe you ought to clarify what the projection $pi$ you refer to is?
    $endgroup$
    – T_M
    Dec 13 '18 at 15:16












  • $begingroup$
    I editted my question @T_M
    $endgroup$
    – User12239
    Dec 13 '18 at 15:19










  • $begingroup$
    isn't the flat metric exactly defined via this property? related to this: math.stackexchange.com/questions/450110/…
    $endgroup$
    – Balou
    Dec 13 '18 at 15:19










  • $begingroup$
    I’m reading DoCarmo’s book and the definition there is different @Balou
    $endgroup$
    – User12239
    Dec 13 '18 at 15:23










  • $begingroup$
    maybe you should state then how "the flat metric" is defined in DoCarmo
    $endgroup$
    – Balou
    Dec 13 '18 at 15:29


















  • $begingroup$
    Maybe you ought to clarify what the projection $pi$ you refer to is?
    $endgroup$
    – T_M
    Dec 13 '18 at 15:16












  • $begingroup$
    I editted my question @T_M
    $endgroup$
    – User12239
    Dec 13 '18 at 15:19










  • $begingroup$
    isn't the flat metric exactly defined via this property? related to this: math.stackexchange.com/questions/450110/…
    $endgroup$
    – Balou
    Dec 13 '18 at 15:19










  • $begingroup$
    I’m reading DoCarmo’s book and the definition there is different @Balou
    $endgroup$
    – User12239
    Dec 13 '18 at 15:23










  • $begingroup$
    maybe you should state then how "the flat metric" is defined in DoCarmo
    $endgroup$
    – Balou
    Dec 13 '18 at 15:29
















$begingroup$
Maybe you ought to clarify what the projection $pi$ you refer to is?
$endgroup$
– T_M
Dec 13 '18 at 15:16






$begingroup$
Maybe you ought to clarify what the projection $pi$ you refer to is?
$endgroup$
– T_M
Dec 13 '18 at 15:16














$begingroup$
I editted my question @T_M
$endgroup$
– User12239
Dec 13 '18 at 15:19




$begingroup$
I editted my question @T_M
$endgroup$
– User12239
Dec 13 '18 at 15:19












$begingroup$
isn't the flat metric exactly defined via this property? related to this: math.stackexchange.com/questions/450110/…
$endgroup$
– Balou
Dec 13 '18 at 15:19




$begingroup$
isn't the flat metric exactly defined via this property? related to this: math.stackexchange.com/questions/450110/…
$endgroup$
– Balou
Dec 13 '18 at 15:19












$begingroup$
I’m reading DoCarmo’s book and the definition there is different @Balou
$endgroup$
– User12239
Dec 13 '18 at 15:23




$begingroup$
I’m reading DoCarmo’s book and the definition there is different @Balou
$endgroup$
– User12239
Dec 13 '18 at 15:23












$begingroup$
maybe you should state then how "the flat metric" is defined in DoCarmo
$endgroup$
– Balou
Dec 13 '18 at 15:29




$begingroup$
maybe you should state then how "the flat metric" is defined in DoCarmo
$endgroup$
– Balou
Dec 13 '18 at 15:29










1 Answer
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Yes; both of these spaces are "flat" in the sense that the curvature of the Riemannian metric is identically zero.






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$endgroup$













  • $begingroup$
    Why does DoCarmo following this question want to prove that the torus with the metric introduced is isometric to the flat torus? Is it not redundant?
    $endgroup$
    – User12239
    Dec 13 '18 at 15:17












  • $begingroup$
    I imagine it's just building familiarity with the rigorous definitions. Just because you know it's true, it certainly doesn't mean that its a pointless exercise
    $endgroup$
    – T_M
    Dec 13 '18 at 19:08











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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









1












$begingroup$

Yes; both of these spaces are "flat" in the sense that the curvature of the Riemannian metric is identically zero.






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Why does DoCarmo following this question want to prove that the torus with the metric introduced is isometric to the flat torus? Is it not redundant?
    $endgroup$
    – User12239
    Dec 13 '18 at 15:17












  • $begingroup$
    I imagine it's just building familiarity with the rigorous definitions. Just because you know it's true, it certainly doesn't mean that its a pointless exercise
    $endgroup$
    – T_M
    Dec 13 '18 at 19:08
















1












$begingroup$

Yes; both of these spaces are "flat" in the sense that the curvature of the Riemannian metric is identically zero.






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Why does DoCarmo following this question want to prove that the torus with the metric introduced is isometric to the flat torus? Is it not redundant?
    $endgroup$
    – User12239
    Dec 13 '18 at 15:17












  • $begingroup$
    I imagine it's just building familiarity with the rigorous definitions. Just because you know it's true, it certainly doesn't mean that its a pointless exercise
    $endgroup$
    – T_M
    Dec 13 '18 at 19:08














1












1








1





$begingroup$

Yes; both of these spaces are "flat" in the sense that the curvature of the Riemannian metric is identically zero.






share|cite|improve this answer









$endgroup$



Yes; both of these spaces are "flat" in the sense that the curvature of the Riemannian metric is identically zero.







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Dec 13 '18 at 15:15









T_MT_M

1,12827




1,12827












  • $begingroup$
    Why does DoCarmo following this question want to prove that the torus with the metric introduced is isometric to the flat torus? Is it not redundant?
    $endgroup$
    – User12239
    Dec 13 '18 at 15:17












  • $begingroup$
    I imagine it's just building familiarity with the rigorous definitions. Just because you know it's true, it certainly doesn't mean that its a pointless exercise
    $endgroup$
    – T_M
    Dec 13 '18 at 19:08


















  • $begingroup$
    Why does DoCarmo following this question want to prove that the torus with the metric introduced is isometric to the flat torus? Is it not redundant?
    $endgroup$
    – User12239
    Dec 13 '18 at 15:17












  • $begingroup$
    I imagine it's just building familiarity with the rigorous definitions. Just because you know it's true, it certainly doesn't mean that its a pointless exercise
    $endgroup$
    – T_M
    Dec 13 '18 at 19:08
















$begingroup$
Why does DoCarmo following this question want to prove that the torus with the metric introduced is isometric to the flat torus? Is it not redundant?
$endgroup$
– User12239
Dec 13 '18 at 15:17






$begingroup$
Why does DoCarmo following this question want to prove that the torus with the metric introduced is isometric to the flat torus? Is it not redundant?
$endgroup$
– User12239
Dec 13 '18 at 15:17














$begingroup$
I imagine it's just building familiarity with the rigorous definitions. Just because you know it's true, it certainly doesn't mean that its a pointless exercise
$endgroup$
– T_M
Dec 13 '18 at 19:08




$begingroup$
I imagine it's just building familiarity with the rigorous definitions. Just because you know it's true, it certainly doesn't mean that its a pointless exercise
$endgroup$
– T_M
Dec 13 '18 at 19:08


















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