Hi,

I'm having test tomorrow, but I have problem with these questions:

1. How to build an anti example that overturns equivalence

$\displaystyle \forall x (P(x) \oplus Q(x)) = \forall x P(x) \oplus \forall x Q(x)

$

2. Given predicate $\displaystyle L (a, b) = "a>b" $

Write predicate expressions:

a) $\displaystyle "a< b < c" $

b) $\displaystyle "a \neq b " $

c) "At least two of the numbers a, b, c are the same"

a, b and c are real numbers