Order(P) and Order(NP) are the number of elements of P and NP respectively, Order(P) and Order(NP) are uncountable variables but they are still comparable to the elementary properties of their respective elements.
For example let's define for the class P the relation R-comptability (L,K)- > { L and K have polynomial relation between their expressed complexities.}
For any element p out of P we have :
Compa(p) = Order(P) - 1
and
Incompa(p) = 0.
Let's define the same relation R-comptability defined previously but for the class NP.
For any element n out of NP we have:
Compa(n) < Order(NP) - 1
and
Incompa(n) > 0
This question of yours brings me to the subject of uncountable variables, which is a subject of research for me.
Regarding the notational question of x|y, it means x is different from y.
About uncountable variables, I believe the number of steps necessary to solve an NP-Hard problem to be an uncountable variable, but this is yet to be proved.