Def  A == A  False

is mentioned by

Thm*  b:. prime(b)  b | 1	[no_prime_divs_one_b]
Thm*  b:. b | 1  prime(b)	[no_prime_divs_one]
Thm*  b:. b | 1  prime(b)	[no_nat_prime_divs_one]
Thm*  x:{2...}. prime(x)  (i,j:{2..x}. x = ij & prime(i))	[composite_with_prime_factor]
Thm*  x:. prime(x)  x<2  (i,j:{2..x}. x = ij)	[nonprime_nat]
Thm*  x:. prime(x)  (i:{2..x}. i | x)	[natprime_nondivs]
Thm*  x:. prime(x)  2x & (i:{2..x}. i | x)	[prime_nat]

In prior sections: core bool 1 rel 1 LogicSupplement int 2 num thy 1

Try larger context: DiscrMathExt IF YOU CAN SEE THIS go to /sfa/Nuprl/Shared/Xindentation_hack_doc.html