unsolved

Unsolved is an adjective applied to matters that have not yet been resolved or explained. It is used across domains, from formal research to everyday problems, to describe questions that remain unanswered or events that lack a definitive explanation.

In mathematics and logic, an unsolved problem is typically called an open problem or open question. These are problems for which no proof or counterexample is known. Notable open problems include the Riemann Hypothesis, the P versus NP problem, and the Collatz conjecture, among others. Some open problems persist for centuries, guiding research as mathematicians attempt to develop new techniques and theories.

In criminal justice and investigative reporting, an unsolved case is one where authorities have not identified a perpetrator or fully explained the circumstances. Such cases may become cold if new evidence remains elusive, and may be reopened if new information emerges.

In science, many questions remain unresolved, spanning physics, biology, earth science, and social science. These unsolved questions drive inquiry and experimentation, and progress often comes gradually as new data, methods, or theories emerge. Examples include unresolved questions about the nature of dark matter and the mechanisms behind quantum gravity, as well as the origins of life.

In culture and media, unsolved mysteries appear in novels, films, and television, where the outcome is deliberately left unresolved to engage audiences. Unsolved topics thus function as a catalyst for continued inquiry and storytelling, across disciplines and genres.