How to succinctly describe a group composed of those for whom a given condition is false and those for whom the state of the condition is not known?

Question

For example, if I'm talking about height, and I want to split the world into two groups based on whether or not I have seen that they are taller than me.

The first group is composed of only the people who are taller than me whom I have also seen.

The second group is composed of everyone I haven't seen — regardless of their height — as well as people whom I have seen who are also shorter than me.

Is there an easy way to express the second group composed of both negatives and unknowns?

Answer 1

The definition of the second group is the negation of the definition of the first group: those whom I do not know to be taller.

Impersonal form: those not known to be taller.

Either way, the construction is well established.