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Conference rusure::math

Title:Mathematics at DEC
Moderator:RUSURE::EDP
Created:Mon Feb 03 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2083
Total number of notes:14613

1324.0. "number theory trivia" by SMAUG::ABBASI () Mon Nov 05 1990 23:07

    I would like to find the status of these problems. have they been
    solved ? or any partial answers if not. 
    
    Test your Number theroy Trivia !
    
    thank you
    --------------------------------------------------------------
    1) are there finite number of twin primes ? 
       is the largest known still this : 1,000,000,009,649   
                                         1,000,000,009,651
    
    2) are there infinite number of perfect numbers? (this relates
       to mersseen (sp?) numbers , since a perfect number is of forum
       2^p(2^(p-1) -1) , where  2^(p-1) - 1  is prime (by Euler), so
       the question can also be asked is there an infinite number
       of mersseen numbers ?
    
    3) what is the largest mersseen(sp?) number known ?
    
    4) what is the largest n for which a solution of  x^n + y^n = z^n
       is known ?
    
    
    5) since it is possible to find 6  consecutive composite
        numbers  by saying  N= 6!= 6*6*5*4*3*2= 720
                 so N+2 = 2[ 6*5*4*3 +1] =722
                    N+3 = 3[ 6*5*4*2 +1] =723
                     .
                     .
                    N+6 = 6[ 5*4*3*2 +1] = 726
       so for 10! we can come with 10 consecutive composite numbers
       following above process. we can come with Huge caps of 
       consective composite numbers, so can I conjecture that since 
       these gaps become so immense, primes will eventually cease to
       occure, so prime are finite .
       can I seay for oo! we can come with oo consectivte composite numbers.
       so prime numbers are not infinite. ?
       whats wrong with the argument.
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1324.1I know that's not what you meant. :-)GUESS::DERAMODan D'EramoTue Nov 06 1990 10:598
>>    4) what is the largest n for which a solution of  x^n + y^n = z^n
>>       is known ?

	Positive integral solutions are known for n = 2 (for example,
	x = 3, y = 4, z = 5, n = 2) but for no larger n.

	Dan
	:-)
1324.2GUESS::DERAMODan D'EramoTue Nov 06 1990 11:1230
>>    5) since it is possible to find 6  consecutive composite
>>        numbers  by saying  N= 6!= 6*6*5*4*3*2= 720
>>                 so N+2 = 2[ 6*5*4*3 +1] =722
>>                    N+3 = 3[ 6*5*4*2 +1] =723
>>                     .
>>                     .
>>                    N+6 = 6[ 5*4*3*2 +1] = 726
>>       so for 10! we can come with 10 consecutive composite numbers
>>       following above process. we can come with Huge caps of 
>>       consective composite numbers, so can I conjecture that since 
>>       these gaps become so immense, primes will eventually cease to
>>       occure, so prime are finite .
>>       can I seay for oo! we can come with oo consectivte composite numbers.
>>       so prime numbers are not infinite. ?
>>       whats wrong with the argument.

	Actually, for N = 6!, N+2 thru N+6 make up only five, not six,
	consecutive composite numbers (although N and N+1 are also
	composite here, for a total of seven consecutive composites).

	Although the gaps becomes arbitrarily large, they do not (as the
	argument incorrectly assumes) become "everything from this point
	on".  As Euclid first showed, there are infinitely many primes.

	In a nonstandard model of, say, Peano arithmetic, if N is
	nonstandard then N!+2, N!+3, N!+4, ... N!+(any standard integer > 1),
	... will all be composite, but there will still be a (nonstandard)
	prime larger than all of those numbers.

	Dan
1324.3any one knows how big oo is??SMAUG::ABBASITue Nov 06 1990 22:4712
    ref .1 
    I really , really meant to ask for largest n that x^n+y^n=z^n has
    been "proved" that this formula is cant be satisfied for integers.
    I read in book dated 1976 that for up to n=600, fermat last theory
    has been proved.
    
    ref .2
    well dan, You affirmed something about my self I always suspected.
    I cant count !  :-)
    
    /naser
    
1324.4by Sam Wagstaff JrHERON::BUCHANANcombinatorial bomb squadWed Nov 07 1990 05:5110
>    ref .1 
>    I really , really meant to ask for largest n that x^n+y^n=z^n has
>    been "proved" that this formula is cant be satisfied for integers.
>    I read in book dated 1976 that for up to n=600, fermat last theory
>    has been proved.

	According to Bob Silverman on the net recently, who knows about
this kind of thing, n is currently 150,000.

Andrew.
1324.5for completenessHERON::BUCHANANcombinatorial bomb squadWed Nov 07 1990 05:5728
>    1) are there finite number of twin primes ? 

	No one knows

>       is the largest known still this : 1,000,000,009,649   
>                                         1,000,000,009,651
 
	No.   A note here eighteen months or so had some much bigger ones
which were (then) the record.
   
>    2) are there infinite number of perfect numbers? (this relates
>       to mersseen (sp?) numbers , since a perfect number is of forum
>       2^p(2^(p-1) -1) , where  2^(p-1) - 1  is prime (by Euler), so
>       the question can also be asked is there an infinite number
>       of mersseen numbers ?
 
	(a) It's Mersenne
	(b) *Even* perfect numbers are in 1-1 correspondence with the Mersenne
primes, but it's unknown whether there is an odd perfect number.
	(c) It's unknown whether there is an infinite number of Mersenne primes.

>    3) what is the largest mersseen(sp?) number known ?
 
	A very early note in this notesfile (one of the first 10, I think)
lists the exponents of all the known Mersenne primes.

Regards,
Andrew.   
1324.6ALLVAX::JROTHIt's a bush recording...Wed Nov 07 1990 08:2710
�    I really , really meant to ask for largest n that x^n+y^n=z^n has
�    been "proved" that this formula is cant be satisfied for integers.
�    I read in book dated 1976 that for up to n=600, fermat last theory
�    has been proved.

    I thought the conjecture was proved to be true for some infinite classes
    of exponents (by Kummer?) but not all of them - if this is so, the correct
    thing to ask is for what n do we know that it is true for all k < n.

    - Jim
1324.7GUESS::DERAMODan D&#039;EramoWed Nov 07 1990 11:0812
�    I thought the conjecture was proved to be true for some infinite classes
�    of exponents (by Kummer?) but not all of them - if this is so, the correct
�    thing to ask is for what n do we know that it is true for all k < n.

	Has it been shown that infinitely many primes satisfy
	his criteria?

	I think there are different limits n for the two cases
	where n divides xyz and where n does not divide xyz (where
	n is assumed to be an odd prime).

	Dan
1324.8Dir/title=fermatCIVAGE::LYNNLynn Yarbrough @WNP DTN 427-5663Wed Nov 07 1990 15:574
>    4) what is the largest n for which a solution of  x^n + y^n = z^n
>       is known ?

See note 445.