Is there any definition of the sum of $n$ summands, when $n$ is not a natural number?

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I think, from the algebraic point of view, that this doesn't make sense, since the addition of $n$ terms is defined "inductively" from the binary operation of the addition. This even yields the formula of $nx = x + x + cdots + x$, where the $x$ is added $n$ times (which I saw as a different operation than the multiplication in a ring, but an action of the natural numbers in the ring).



However, it would make sense to make a definition of adding $n in mathbbRsetminusmathbbN$ terms or summands? Something like the sense of a fractional derivative?







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    I think, from the algebraic point of view, that this doesn't make sense, since the addition of $n$ terms is defined "inductively" from the binary operation of the addition. This even yields the formula of $nx = x + x + cdots + x$, where the $x$ is added $n$ times (which I saw as a different operation than the multiplication in a ring, but an action of the natural numbers in the ring).



    However, it would make sense to make a definition of adding $n in mathbbRsetminusmathbbN$ terms or summands? Something like the sense of a fractional derivative?







    share|cite|improve this question























      up vote
      1
      down vote

      favorite









      up vote
      1
      down vote

      favorite











      I think, from the algebraic point of view, that this doesn't make sense, since the addition of $n$ terms is defined "inductively" from the binary operation of the addition. This even yields the formula of $nx = x + x + cdots + x$, where the $x$ is added $n$ times (which I saw as a different operation than the multiplication in a ring, but an action of the natural numbers in the ring).



      However, it would make sense to make a definition of adding $n in mathbbRsetminusmathbbN$ terms or summands? Something like the sense of a fractional derivative?







      share|cite|improve this question













      I think, from the algebraic point of view, that this doesn't make sense, since the addition of $n$ terms is defined "inductively" from the binary operation of the addition. This even yields the formula of $nx = x + x + cdots + x$, where the $x$ is added $n$ times (which I saw as a different operation than the multiplication in a ring, but an action of the natural numbers in the ring).



      However, it would make sense to make a definition of adding $n in mathbbRsetminusmathbbN$ terms or summands? Something like the sense of a fractional derivative?









      share|cite|improve this question












      share|cite|improve this question




      share|cite|improve this question








      edited Jul 24 at 11:49
























      asked Jul 24 at 4:36









      Manuel Sánchez

      84




      84




















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          Markus Muller and Dierk Schleicher say there is.



          http://www.mpmueller.net/HowToAdd.pdf






          share|cite|improve this answer





















          • I love that people took the time to make sense of something so seemingly nonsensical!
            – Sambo
            Jul 24 at 16:52










          • Amazing. It's surprising that there's not many articles about those kind of definitions. Another article I found (same authors) can be found here: arxiv.org/abs/math/0502109
            – Manuel Sánchez
            Jul 31 at 5:06










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          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes








          up vote
          3
          down vote



          accepted










          Markus Muller and Dierk Schleicher say there is.



          http://www.mpmueller.net/HowToAdd.pdf






          share|cite|improve this answer





















          • I love that people took the time to make sense of something so seemingly nonsensical!
            – Sambo
            Jul 24 at 16:52










          • Amazing. It's surprising that there's not many articles about those kind of definitions. Another article I found (same authors) can be found here: arxiv.org/abs/math/0502109
            – Manuel Sánchez
            Jul 31 at 5:06














          up vote
          3
          down vote



          accepted










          Markus Muller and Dierk Schleicher say there is.



          http://www.mpmueller.net/HowToAdd.pdf






          share|cite|improve this answer





















          • I love that people took the time to make sense of something so seemingly nonsensical!
            – Sambo
            Jul 24 at 16:52










          • Amazing. It's surprising that there's not many articles about those kind of definitions. Another article I found (same authors) can be found here: arxiv.org/abs/math/0502109
            – Manuel Sánchez
            Jul 31 at 5:06












          up vote
          3
          down vote



          accepted







          up vote
          3
          down vote



          accepted






          Markus Muller and Dierk Schleicher say there is.



          http://www.mpmueller.net/HowToAdd.pdf






          share|cite|improve this answer













          Markus Muller and Dierk Schleicher say there is.



          http://www.mpmueller.net/HowToAdd.pdf







          share|cite|improve this answer













          share|cite|improve this answer



          share|cite|improve this answer











          answered Jul 24 at 4:49









          Steve B

          34126




          34126











          • I love that people took the time to make sense of something so seemingly nonsensical!
            – Sambo
            Jul 24 at 16:52










          • Amazing. It's surprising that there's not many articles about those kind of definitions. Another article I found (same authors) can be found here: arxiv.org/abs/math/0502109
            – Manuel Sánchez
            Jul 31 at 5:06
















          • I love that people took the time to make sense of something so seemingly nonsensical!
            – Sambo
            Jul 24 at 16:52










          • Amazing. It's surprising that there's not many articles about those kind of definitions. Another article I found (same authors) can be found here: arxiv.org/abs/math/0502109
            – Manuel Sánchez
            Jul 31 at 5:06















          I love that people took the time to make sense of something so seemingly nonsensical!
          – Sambo
          Jul 24 at 16:52




          I love that people took the time to make sense of something so seemingly nonsensical!
          – Sambo
          Jul 24 at 16:52












          Amazing. It's surprising that there's not many articles about those kind of definitions. Another article I found (same authors) can be found here: arxiv.org/abs/math/0502109
          – Manuel Sánchez
          Jul 31 at 5:06




          Amazing. It's surprising that there's not many articles about those kind of definitions. Another article I found (same authors) can be found here: arxiv.org/abs/math/0502109
          – Manuel Sánchez
          Jul 31 at 5:06












           

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