Let a b c and d be real numbers such that a SolutionThe axio
     Let a, b, c and d be real numbers such that a  
  
  Solution
The axiom of choice is equivalent to the statement that | c |  |d | or | d|  | c| for every c,d
 Let f(x) = c( xb/ ab ) + d( xa/ ba ).
 Then f : [a, b]  [c, d] one-to-one and onto f : (a, b)  (c, d) one-to-one and onto
 So that
 If | a| < | b |
 then | A | = | B | (Cantor–Bernstein–Schroeder theorem)
 The axiom of choice is equivalent to the statement that | a |  |b | or | b |  | a| for every a.b
 | c | < | d |
 So that
 (axb)x(cxd)--------1
 Lets say axb=x
 Xx(cxd)=(x.d).c-(x.c.d)-----2
 Then
 x.d=(axb).d
 =a.(bxd)
 x.c=(axb).c
 =a.(bxc)
 Su statute in 2 we get
 L.H.S=
 {a.(bxd)}.c-{a.(bxc)}.d=constant

