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Re: Mathematics, Java, good enough

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From	Eric Sosman <esosman@comcast-dot-net.invalid>
Newsgroups	comp.lang.java.programmer
Subject	Re: Mathematics, Java, good enough
Date	Tue, 17 May 2016 14:09:25 -0400
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On 5/17/2016 1:15 PM, Duncan Idaho wrote:
> On 17/05/16 15:43, Stefan Ram wrote:
>> Duncan Idaho <duncan@dunenoemail.com> writes:
>>> how many strings of length L are possible from
>> ...
>>> a set of characters S of cardinality C
>>
>>    If an alphabet has C members, there are C^L words of length
>>    L over it, because for every word position, there are C choices,
>>    and the choices of positions multiply as one can easily see.
>>
>>    For example, an octet of bit memory cells has java.lang.Math.pow
>>    ( 2, 8 ) possible states. A UHD screen with 24 bits of color can
>>    show java.math.BigInteger.valueOf( 2<<23 ).pow( 7680 * 4320 )
>>    different pictures.
>
> hmm
>
> That last one was too easy for you guys obviously :-)
>
> So what if I said how many *sets* of cardinality C are there in a set S
> of cardinality SC
>
> Example
> so where C = 8 then "ABCDEFGH" is good but "AABCDEFG" isn't

     Your terminology isn't too clear; what does "in" mean?

     But *if* you mean "How many 8-character strings can I make from
a 62-character alphabet, with no repetitions?" that's an easy one:

	62 * 61 * 60 * 59 * 58 * 57 * 56 * 55

also known as

	62! / (62-8)! ~= 1.4E14

-- 
esosman@comcast-dot-net.invalid
"Don't be afraid of work. Make work afraid of you." -- TLM

Thread

Mathematics, Java, good enough Duncan Idaho <duncan@dunenoemail.com> - 2016-05-17 11:49 +0100
  Re: Mathematics, Java, good enough Eric Douglas <e.d.programmer@gmail.com> - 2016-05-17 04:55 -0700
  Re: Mathematics, Java, good enough Nigel Wade <nmw@ion.le.ac.uk> - 2016-05-17 12:56 +0100
    Re: Mathematics, Java, good enough Nigel Wade <nmw@ion.le.ac.uk> - 2016-05-17 13:06 +0100
    Re: Mathematics, Java, good enough Duncan Idaho <duncan@dunenoemail.com> - 2016-05-17 13:29 +0100
      Re: Mathematics, Java, good enough Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-05-17 09:54 -0400
        Re: Mathematics, Java, good enough FredK <fred.l.kleinschmidt@gmail.com> - 2016-05-17 07:17 -0700
          Re: Mathematics, Java, good enough FredK <fred.l.kleinschmidt@gmail.com> - 2016-05-17 07:29 -0700
            Re: Mathematics, Java, good enough Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-05-17 10:58 -0400
              Re: Mathematics, Java, good enough Duncan Idaho <duncan@dunenoemail.com> - 2016-05-17 18:10 +0100
                Re: Mathematics, Java, good enough Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-05-17 14:02 -0400
                Re: Mathematics, Java, good enough Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-05-17 14:10 -0400
                Re: Mathematics, Java, good enough Eric Douglas <e.d.programmer@gmail.com> - 2016-05-17 11:36 -0700
                Re: Mathematics, Java, good enough Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-05-17 16:12 -0400
                Re: Mathematics, Java, good enough Eric Douglas <e.d.programmer@gmail.com> - 2016-05-17 13:56 -0700
                Re: Mathematics, Java, good enough Gene Wirchenko <genew@telus.net> - 2016-05-17 14:13 -0700
                Re: Mathematics, Java, good enough Duncan Idaho <duncan@dunenoemail.com> - 2016-05-18 05:06 +0100
  Re: Mathematics, Java, good enough Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-05-17 08:25 -0400
  Re: Mathematics, Java, good enough Martin Gregorie <martin@address-in-sig.invalid> - 2016-05-17 12:24 +0000
  Re: Mathematics, Java, good enough Duncan Idaho <duncan@dunenoemail.com> - 2016-05-17 18:15 +0100
    Re: Mathematics, Java, good enough Jerry Stuckle <jstucklex@attglobal.net> - 2016-05-17 13:33 -0400
    Re: Mathematics, Java, good enough Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-05-17 14:09 -0400
      Re: Mathematics, Java, good enough Gene Wirchenko <genew@telus.net> - 2016-05-17 14:17 -0700
        Re: Mathematics, Java, good enough Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-05-17 17:49 -0400

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