Odd primes...

Several students were asked the following problem:

        Prove that all odd integers are prime.

Well, the first student to try to do this was a math student.  He
says "Hmmm...  Well, 1 is prime, 3 is prime, 5 is prime, and by
induction, we have that all the odd integers are prime."

Of course, there are some jeers from some of his friends.  The physics
student then said, "I'm not sure of the validity of your proof, but I
think I'll try to prove it by experiment."  He continues, "Well, 1 is
prime, 3 is prime, 5 is prime, 7 is prime, 9 is ... uh, 9 is an
experimental error, 11 is prime, 13 is prime...  Well, it seems that
you're right."

The third student to try it was the engineering student, who
responded, "Well, actually, I'm not sure of your answer either.  Let's
see... 1 is prime, 3 is prime, 5 is prime, 7 is prime, 9 is ..., 9 is
..., well if you approximate, 9 is prime, 11 is prime, 13 is prime...
Well, it does seem right."

Not to be outdone, the computer science student comes along and says
"Well, you two sort've got the right idea, but you'd end up taking too
long doing it.  I've just whipped up a program to REALLY go and prove
it..."  He goes over to his terminal and runs his program.  Reading
the output on the screen he says, "1 is prime, 1 is prime, 1 is prime,
1 is prime...."

-----------------------------------------------------------------------------

Mathematician: 3 is a prime, 5 is a prime, 7 is a prime,
               9 is not a prime - counter-example - claim is false.

Physicist: 3 is a prime, 5 is a prime, 7 is a prime,
           9 is an experimental error, 11 is a prime, ...

Engineer: 3 is a prime, 5 is a prime, 7 is a prime,
          9 is a prime, 11 is a prime, ...

Computer scientist: 3's a prime, 5's a prime, 7's a prime, 7's a prime,
                    7's a prime, ...

Computer scientist using Unix: 3's a prime, 5's a prime, 7's a prime,
                               segmentation fault

Gosh, they all overlooked that even 2's a prime!!

I figure that 2 is the oddest prime of all, because it's the
only one that's even!

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This message was sent on 12 Apr 1996