Learn English – Word that describes a problem that is missing a precondition

single-word-requestsword-choice

I'm an engineer, and sometimes I want to describe a problem that is unresolvable in its current state. The problem might be easy, or somewhat complex, but the key aspects of it are understood and it cannot be solved without changing some other condition.

An example:

  • Deliver this physical letter from our location in the US to this address in Cambodia.
    It must arrive within 10 minutes.

This problem is understandable, but it is not (practically?) possible. If the requirements are changed to allow digital transmission, it can be done.

Another example, emphasizing that the problem is not too little information, but competing requirements which are incongruent with a single solution:

  • Describe a physical object which meets all the following criteria:
    Is as big as bread basket
    Is colored red
    Is invisible

In this case, coloring the thing and having the thing be invisible are incompatible.

Or the classic:

  • Car Repair:
    Fast
    Cheap
    Done Right

Choose any 2, as the joke goes. All 3 are at the same time are… insoluble? irresolvable? This is the word I'm looking for.

Hopefully these analogies communicate my point, I wanted to avoid tech jargon.

These problems could be described as:

  • Inextricable — "Too involved or complicated to solve. Extremely intricate." Not really. Complexity is not in the way of a solution here.
  • Inscrutable — "Incapable of being investigated, analyzed, or scrutinized; impenetrable. Not easily understood; mysterious; unfathomable:". Closer, but the definition implies some complexity in the problem itself which I don't want to communicate.
  • Unsolvable — "[Not] capable of being solved, as a problem.". Completely accurate, but could be more descriptive. Why isn't the problem solvable?

Similar:
Insolvable, insoluble, and unsolvable

Best Answer

You seem to have two different kinds of examples there. In the first example the solution set is ill-defined:

A set is well-defined if any given object either is an element of the set, or is not an element of the set

but it's never clear whether a given number a is an element of the solution set to the equation; whether it is or not depends (as you state) on the value of b.

In your second example, the solution set (that is, the set of solutions to the problem posed) is well-defined, but empty because the conditions are impracticable:

(Definition 2) not practicable : incapable of being performed or accomplished by the means employed or at command

Related Topic