“Cyclic” continuum

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On p. 221 of http://topology.auburn.edu/tp/reprints/v08/tp08113.pdf, I found the following definition:



"A curve is said to be cyclic if its first Čech cohomology group with integer coefficients does not vanish".



Here, a curve means a homogeneous metric continuum of dimension 1.



Can someone explain this definition in different, more elementary, terms, and give some examples to illustrate the meaning?










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    On p. 221 of http://topology.auburn.edu/tp/reprints/v08/tp08113.pdf, I found the following definition:



    "A curve is said to be cyclic if its first Čech cohomology group with integer coefficients does not vanish".



    Here, a curve means a homogeneous metric continuum of dimension 1.



    Can someone explain this definition in different, more elementary, terms, and give some examples to illustrate the meaning?










    share|cite|improve this question









    New contributor




    Douglas Sirk is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.





















      up vote
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      On p. 221 of http://topology.auburn.edu/tp/reprints/v08/tp08113.pdf, I found the following definition:



      "A curve is said to be cyclic if its first Čech cohomology group with integer coefficients does not vanish".



      Here, a curve means a homogeneous metric continuum of dimension 1.



      Can someone explain this definition in different, more elementary, terms, and give some examples to illustrate the meaning?










      share|cite|improve this question









      New contributor




      Douglas Sirk is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.











      On p. 221 of http://topology.auburn.edu/tp/reprints/v08/tp08113.pdf, I found the following definition:



      "A curve is said to be cyclic if its first Čech cohomology group with integer coefficients does not vanish".



      Here, a curve means a homogeneous metric continuum of dimension 1.



      Can someone explain this definition in different, more elementary, terms, and give some examples to illustrate the meaning?







      gn.general-topology cohomology definitions






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      Amir Sagiv

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          Perhaps the first Čech cohomology group with integer coefficients may seem not elementary. Then use the characterization of it as the first Borsuk's cohomotopy group (or it appears as the Brushlinsky's group in the well-known text on Homotopy Theory by Hu). This group's elements are simply the homotopy classes of mappings into $ mathbb S^1.$ Space $ S^1 $ is a topological group, it induces the group structure on the homotopy classes.






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            Perhaps the first Čech cohomology group with integer coefficients may seem not elementary. Then use the characterization of it as the first Borsuk's cohomotopy group (or it appears as the Brushlinsky's group in the well-known text on Homotopy Theory by Hu). This group's elements are simply the homotopy classes of mappings into $ mathbb S^1.$ Space $ S^1 $ is a topological group, it induces the group structure on the homotopy classes.






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              Perhaps the first Čech cohomology group with integer coefficients may seem not elementary. Then use the characterization of it as the first Borsuk's cohomotopy group (or it appears as the Brushlinsky's group in the well-known text on Homotopy Theory by Hu). This group's elements are simply the homotopy classes of mappings into $ mathbb S^1.$ Space $ S^1 $ is a topological group, it induces the group structure on the homotopy classes.






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                up vote
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                Perhaps the first Čech cohomology group with integer coefficients may seem not elementary. Then use the characterization of it as the first Borsuk's cohomotopy group (or it appears as the Brushlinsky's group in the well-known text on Homotopy Theory by Hu). This group's elements are simply the homotopy classes of mappings into $ mathbb S^1.$ Space $ S^1 $ is a topological group, it induces the group structure on the homotopy classes.






                share|cite|improve this answer












                Perhaps the first Čech cohomology group with integer coefficients may seem not elementary. Then use the characterization of it as the first Borsuk's cohomotopy group (or it appears as the Brushlinsky's group in the well-known text on Homotopy Theory by Hu). This group's elements are simply the homotopy classes of mappings into $ mathbb S^1.$ Space $ S^1 $ is a topological group, it induces the group structure on the homotopy classes.







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                answered 1 hour ago









                Wlod AA

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