When thinking about these things I occasionally find it useful to use intervals instead of numbers to represent probabilities and utilities:
P(U) is in (0, epsilon), where epsilon is the lowest upper bound for the probability I found before I ran out of RAM.
P(V) is in (1 - epsilon, 1).
P(W) is in (0, 1); or in (a, b) if I managed to find nontrivial bounds a and b before I ran out of RAM.
U(X) is in (N, infinity)
U(Y) is in (-infinity, N)
U(Z) is in (-infinity, infinity); or (M, N) if I managed to find finite upper or lower bounds before running out of RAM.
EDIT: This might be what is known as “interval-valued probabilities” in the literature.
When thinking about these things I occasionally find it useful to use intervals instead of numbers to represent probabilities and utilities:
P(U) is in (0, epsilon), where epsilon is the lowest upper bound for the probability I found before I ran out of RAM.
P(V) is in (1 - epsilon, 1).
P(W) is in (0, 1); or in (a, b) if I managed to find nontrivial bounds a and b before I ran out of RAM.
U(X) is in (N, infinity)
U(Y) is in (-infinity, N)
U(Z) is in (-infinity, infinity); or (M, N) if I managed to find finite upper or lower bounds before running out of RAM.
EDIT: This might be what is known as “interval-valued probabilities” in the literature.