They first considered a simple decision problem comprised by 3 alternatives and 2 criteria.

That new state will then affect the decision problem from time 1 on.

The whole future decision problem appears inside the square brackets on the right.

An example of a decision problem is the following.

That's a yes/no question, so this is a decision problem.

Formally, a decision problem is a subset of the natural numbers.

In contrast, the decision problem "is N a composite number?"

The decision problem then is to decide whether such a solution exists or not.

The best known work of his Soviet period is on the classical decision problem.

A decision problem is represented as a set A of natural numbers (or strings).