unicity of a 1-form












0












$begingroup$


I read somewhere that if the 1st cohomology group of a manifold is trivial, then it contains a 1-form that is unique up to an exact form.



Is this statement true?



Thank you!










share|cite|improve this question









$endgroup$








  • 2




    $begingroup$
    If the first de Rham cohomology group is trivial, then every closed one-form is exact, but there are plenty of non-exact one-forms.
    $endgroup$
    – Michael Albanese
    Dec 22 '18 at 0:20










  • $begingroup$
    Are you sure? if the first Rham cohomology group is trivial, then every closed form is exact, there can be no non-exact 1-form, since the Rham cohomology group is the quotient of closed forms over exact forms. Could you please give details?
    $endgroup$
    – PerelMan
    Dec 22 '18 at 0:46








  • 1




    $begingroup$
    The point is that not every form is closed.
    $endgroup$
    – Aleksandar Milivojevic
    Jan 5 at 20:49
















0












$begingroup$


I read somewhere that if the 1st cohomology group of a manifold is trivial, then it contains a 1-form that is unique up to an exact form.



Is this statement true?



Thank you!










share|cite|improve this question









$endgroup$








  • 2




    $begingroup$
    If the first de Rham cohomology group is trivial, then every closed one-form is exact, but there are plenty of non-exact one-forms.
    $endgroup$
    – Michael Albanese
    Dec 22 '18 at 0:20










  • $begingroup$
    Are you sure? if the first Rham cohomology group is trivial, then every closed form is exact, there can be no non-exact 1-form, since the Rham cohomology group is the quotient of closed forms over exact forms. Could you please give details?
    $endgroup$
    – PerelMan
    Dec 22 '18 at 0:46








  • 1




    $begingroup$
    The point is that not every form is closed.
    $endgroup$
    – Aleksandar Milivojevic
    Jan 5 at 20:49














0












0








0





$begingroup$


I read somewhere that if the 1st cohomology group of a manifold is trivial, then it contains a 1-form that is unique up to an exact form.



Is this statement true?



Thank you!










share|cite|improve this question









$endgroup$




I read somewhere that if the 1st cohomology group of a manifold is trivial, then it contains a 1-form that is unique up to an exact form.



Is this statement true?



Thank you!







differential-geometry






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Dec 22 '18 at 0:03









PerelManPerelMan

760414




760414








  • 2




    $begingroup$
    If the first de Rham cohomology group is trivial, then every closed one-form is exact, but there are plenty of non-exact one-forms.
    $endgroup$
    – Michael Albanese
    Dec 22 '18 at 0:20










  • $begingroup$
    Are you sure? if the first Rham cohomology group is trivial, then every closed form is exact, there can be no non-exact 1-form, since the Rham cohomology group is the quotient of closed forms over exact forms. Could you please give details?
    $endgroup$
    – PerelMan
    Dec 22 '18 at 0:46








  • 1




    $begingroup$
    The point is that not every form is closed.
    $endgroup$
    – Aleksandar Milivojevic
    Jan 5 at 20:49














  • 2




    $begingroup$
    If the first de Rham cohomology group is trivial, then every closed one-form is exact, but there are plenty of non-exact one-forms.
    $endgroup$
    – Michael Albanese
    Dec 22 '18 at 0:20










  • $begingroup$
    Are you sure? if the first Rham cohomology group is trivial, then every closed form is exact, there can be no non-exact 1-form, since the Rham cohomology group is the quotient of closed forms over exact forms. Could you please give details?
    $endgroup$
    – PerelMan
    Dec 22 '18 at 0:46








  • 1




    $begingroup$
    The point is that not every form is closed.
    $endgroup$
    – Aleksandar Milivojevic
    Jan 5 at 20:49








2




2




$begingroup$
If the first de Rham cohomology group is trivial, then every closed one-form is exact, but there are plenty of non-exact one-forms.
$endgroup$
– Michael Albanese
Dec 22 '18 at 0:20




$begingroup$
If the first de Rham cohomology group is trivial, then every closed one-form is exact, but there are plenty of non-exact one-forms.
$endgroup$
– Michael Albanese
Dec 22 '18 at 0:20












$begingroup$
Are you sure? if the first Rham cohomology group is trivial, then every closed form is exact, there can be no non-exact 1-form, since the Rham cohomology group is the quotient of closed forms over exact forms. Could you please give details?
$endgroup$
– PerelMan
Dec 22 '18 at 0:46






$begingroup$
Are you sure? if the first Rham cohomology group is trivial, then every closed form is exact, there can be no non-exact 1-form, since the Rham cohomology group is the quotient of closed forms over exact forms. Could you please give details?
$endgroup$
– PerelMan
Dec 22 '18 at 0:46






1




1




$begingroup$
The point is that not every form is closed.
$endgroup$
– Aleksandar Milivojevic
Jan 5 at 20:49




$begingroup$
The point is that not every form is closed.
$endgroup$
– Aleksandar Milivojevic
Jan 5 at 20:49










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