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Is there a name for this class of 'surfaces'? Have they been studied?


Example for divisors, line bundles and meromorphic functions on $mathbb{CP}^2$Has this subset-sum game been studied?Encoding the answers to questions somewhere in a binary treeHas this number triangle been studied?Have “algebraic angles” been studied before?Have “$delta$-measures” (or anything like them) been studied before?Has this functional been studied somewhere?Has this “generalized standard deviation” been studied?degree of line bundle as an integralHas this topology been studied?













4












$begingroup$


I found a page in one of my notebooks describing a particular class of 'surfaces' which are given by the implicit equations:



$$frac{1}{x}+frac{1}{y}+frac{1}{z}=frac{1}{x+y+z}$$



Or, more generally



$$sum_i left(a_ix_i+b_iright)^{-1}=left(sum_ia_ix_i+b_iright)^{-1}quad:quadmathbf{x}inmathbb{R}^n$$



I only have notes on $mathbf{x}inmathbb{R}^2,mathbb{R}^3$ and I'm not sure what the context was at the time I wrote it, but it looks interesting enough and I would like to know more.



Do these objects have a name? Have they been studied before?





Edit:



After working on it for a bit, it occurred to me that in three dimensions this is the same as



$$(u_1+u_2)(u_1+u_3)(u_2+u_3)=0quad:quad u_i=a_ix_i+b_i$$



Which is a particular case of



$$({u_1}^n+{u_2}^n)({u_1}^n+{u_3}^n)({u_2}^n+{u_3}^n)=0$$



For whatever reason, this last bit seems incredibly familiar. I'm not sure why, but it brings to mind something about quaternions, vector norms, and general relativity. Where have I seen this before?










share|cite|improve this question











$endgroup$

















    4












    $begingroup$


    I found a page in one of my notebooks describing a particular class of 'surfaces' which are given by the implicit equations:



    $$frac{1}{x}+frac{1}{y}+frac{1}{z}=frac{1}{x+y+z}$$



    Or, more generally



    $$sum_i left(a_ix_i+b_iright)^{-1}=left(sum_ia_ix_i+b_iright)^{-1}quad:quadmathbf{x}inmathbb{R}^n$$



    I only have notes on $mathbf{x}inmathbb{R}^2,mathbb{R}^3$ and I'm not sure what the context was at the time I wrote it, but it looks interesting enough and I would like to know more.



    Do these objects have a name? Have they been studied before?





    Edit:



    After working on it for a bit, it occurred to me that in three dimensions this is the same as



    $$(u_1+u_2)(u_1+u_3)(u_2+u_3)=0quad:quad u_i=a_ix_i+b_i$$



    Which is a particular case of



    $$({u_1}^n+{u_2}^n)({u_1}^n+{u_3}^n)({u_2}^n+{u_3}^n)=0$$



    For whatever reason, this last bit seems incredibly familiar. I'm not sure why, but it brings to mind something about quaternions, vector norms, and general relativity. Where have I seen this before?










    share|cite|improve this question











    $endgroup$















      4












      4








      4





      $begingroup$


      I found a page in one of my notebooks describing a particular class of 'surfaces' which are given by the implicit equations:



      $$frac{1}{x}+frac{1}{y}+frac{1}{z}=frac{1}{x+y+z}$$



      Or, more generally



      $$sum_i left(a_ix_i+b_iright)^{-1}=left(sum_ia_ix_i+b_iright)^{-1}quad:quadmathbf{x}inmathbb{R}^n$$



      I only have notes on $mathbf{x}inmathbb{R}^2,mathbb{R}^3$ and I'm not sure what the context was at the time I wrote it, but it looks interesting enough and I would like to know more.



      Do these objects have a name? Have they been studied before?





      Edit:



      After working on it for a bit, it occurred to me that in three dimensions this is the same as



      $$(u_1+u_2)(u_1+u_3)(u_2+u_3)=0quad:quad u_i=a_ix_i+b_i$$



      Which is a particular case of



      $$({u_1}^n+{u_2}^n)({u_1}^n+{u_3}^n)({u_2}^n+{u_3}^n)=0$$



      For whatever reason, this last bit seems incredibly familiar. I'm not sure why, but it brings to mind something about quaternions, vector norms, and general relativity. Where have I seen this before?










      share|cite|improve this question











      $endgroup$




      I found a page in one of my notebooks describing a particular class of 'surfaces' which are given by the implicit equations:



      $$frac{1}{x}+frac{1}{y}+frac{1}{z}=frac{1}{x+y+z}$$



      Or, more generally



      $$sum_i left(a_ix_i+b_iright)^{-1}=left(sum_ia_ix_i+b_iright)^{-1}quad:quadmathbf{x}inmathbb{R}^n$$



      I only have notes on $mathbf{x}inmathbb{R}^2,mathbb{R}^3$ and I'm not sure what the context was at the time I wrote it, but it looks interesting enough and I would like to know more.



      Do these objects have a name? Have they been studied before?





      Edit:



      After working on it for a bit, it occurred to me that in three dimensions this is the same as



      $$(u_1+u_2)(u_1+u_3)(u_2+u_3)=0quad:quad u_i=a_ix_i+b_i$$



      Which is a particular case of



      $$({u_1}^n+{u_2}^n)({u_1}^n+{u_3}^n)({u_2}^n+{u_3}^n)=0$$



      For whatever reason, this last bit seems incredibly familiar. I'm not sure why, but it brings to mind something about quaternions, vector norms, and general relativity. Where have I seen this before?







      algebraic-geometry reference-request terminology complex-geometry






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Mar 21 at 21:57







      R. Burton

















      asked Mar 19 at 16:39









      R. BurtonR. Burton

      732110




      732110






















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