assertion in first order logic
Expressing properties of elements of the universe in first order logic is mostly achieved through defining appropriate relations. So for this you might like to consider relations like:


$P(x)$ - $x$ is a person,
$C(x)$ - $x$ is a course,
$Pre(x,y)$ - $x$ is a prerequisite of $y$ (note that this doesn't actually say that $x$ and $y$ are courses),
$Pass(x,y)$ - $x$ has passed course $y$.


(The parentheses are just included for clarity - you may have seen different notation where relations are written without.)

Then the rest is just building the logical formula, which in this case should be fairly obvious.


   $notready(x,a) \equiv P(x) \wedge C(a) \wedge \exists y(C(y) \wedge Pre(y,a) \wedge \neg Pass(x,y)) $