Author steven.daprano
Recipients David Radcliffe, FR4NKESTI3N, josh.r, jwilk, kellerfuchs, mark.dickinson, pablogsal, rhettinger, serhiy.storchaka, steven.daprano, tim.peters
Date 2019-06-03.11:40:50
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Message-id <20190603114029.GX4221@ando.pearwood.info>
In-reply-to <1559528863.09.0.855921596654.issue35431@roundup.psfhosted.org>
Content
For what its worth, there are concrete, practical applications for 
binomial coefficients with negative arguments. They are used in 
fractional calculus

https://nrich.maths.org/1365

which in turn has applications in physics, chemistry and other sciences:

https://en.wikipedia.org/wiki/Fractional_calculus#Applications

Take that however you see fit :-)

My own preference is for a comb() function that returns 0 for out of 
bounds values (e.g. "choose 5 items from 4"), and a seperate binomial() 
function that accepts any positive or negative integer values. Even I 
think that fractional and complex arguments are probably a bit too 
exotic for the std lib -- that's Mathematica territory.

And yes, Mathematica does accept fractional and complex arguments to 
the choose() function.

https://www.wolframalpha.com/input/?i=choose%28sqr%28-3.5%29,+sqrt%28-4%2Bi%29%29
History
Date User Action Args
2019-06-03 11:40:50steven.dapranosetrecipients: + steven.daprano, tim.peters, rhettinger, mark.dickinson, jwilk, serhiy.storchaka, josh.r, pablogsal, kellerfuchs, FR4NKESTI3N, David Radcliffe
2019-06-03 11:40:50steven.dapranolinkissue35431 messages
2019-06-03 11:40:50steven.dapranocreate