• loppy@fedia.io
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    6 hours ago

    Planes can be thought of as spheres of infinite radius, and have infinite surface area. This point of view is very natural in conformal geometry.

  • Zwuzelmaus@feddit.org
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    8 hours ago

    If the radius is infinite

    If the radius is >0 and the definition of sphere is used in infinite-dimensional space.

      • LifeInMultipleChoice@lemmy.world
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        11 hours ago

        I read it as surface area, thus being the amount of space on the sphere itself.

        A=4πr2 is the formula if I remember correctly, so I just figure only radius can be altered to match infinity.

        Maybe someone will tell me I’m missing something

        • thebestaquaman@lemmy.world
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          9 hours ago

          I believe the surface area of an n-dimensional hypersphere is (n - 1) pi r^{n - 1}. In that case (I may have some factors wrong here, just going off memory), an infinite-dimensional hypersphere has infinite surface area as long as it has non-zero radius.

          • loppy@fedia.io
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            4 hours ago

            It does indeed scale with r^(n-1), but your factors are not close at all. It involves the gamma function, which in this case can be expanded into various factorials and also a factor of sqrt(pi) when n is odd. According to Wikipedia, the expression is 2pi(n/2)r(n-1)/Gamma(n/2).

    • mumblerfish@lemmy.world
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      11 hours ago

      one can further prove that the sphere S**n−1 can be partitioned into as many pieces as there are real numbers (that is, {isplaystyle 2^{leph {0}}}pieces)

      Would the answer to OP be some argument along the lines of defining the surface area of the ball as the sum of the partitioned balls surface areas then?