Quadvalued

Quadvalued refers to a data type or concept that can hold one of four distinct values. This is in contrast to binary, which holds two values, or ternary, which holds three values. The specific nature of these four values depends on the context in which quadvalued is used.

In computing, quadvalued logic systems are a generalization of Boolean logic. Instead of just true and false, quadvalued logic might include notions of both true and false, as well as undefined or irrelevant states. These systems are explored in areas like artificial intelligence and formal methods, where nuanced representation of information is required.

Beyond formal logic, the term can be applied more broadly. For example, a system might have a status that can be one of four states: 'active', 'inactive', 'pending', or 'error'. This would be a quadvalued status. Similarly, a sensor might return a reading that falls into one of four categories or ranges. The key characteristic is the limitation to exactly four possible states or values for a given variable or attribute. This concept is fundamental in designing systems that need to represent a limited but not trivial number of distinct conditions.