Re: Re: Re: What is the fastest pure-Perl implementation of XXX?

Only by definition and because it's useful. 0! can just as easily be defined as 0, with different results.

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Comment on Re: Re: Re: What is the fastest pure-Perl implementation of XXX?

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Re: Re: Re: Re: What is the fastest pure-Perl implementation of XXX? by tilly (Archbishop) on Mar 31, 2004 at 19:30 UTC
To the extent that "factorial" is an arbitrary function, you can define it any way that you like. This is trivially obvious, but not very useful. But you will have a very hard time finding any mathematician who agrees that it either makes sense or is useful to define 0! as anything other than 1. I can think of a half-dozen reasons to make it 1. None to call it 0. If you did find such an odd mathematician, I guarantee that it won't be someone in combinatorics (which is the field of math where factorial tends to come up the most).	[reply]

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Re: Re: Re: Re: What is the fastest pure-Perl implementation of XXX?
by tilly (Archbishop) on Mar 31, 2004 at 19:30 UTC

But you will have a very hard time finding any mathematician who agrees that it either makes sense or is useful to define 0! as anything other than 1. I can think of a half-dozen reasons to make it 1. None to call it 0. If you did find such an odd mathematician, I guarantee that it won't be someone in combinatorics (which is the field of math where factorial tends to come up the most).

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