What are logical statements that express facts and relationships called?

Logical statements that express facts and relationships are referred to as predicate logic. Predicate logic extends propositional logic by incorporating predicates and quantifiers, which allow for more complex expressions about objects and their relationships. It provides a formal foundation for reasoning about properties of objects and the relations between them.

For instance, in predicate logic, one can express statements like "All humans are mortal" using quantifiers and predicates, which describe a relationship between the classes of "humans" and "mortality." This is fundamentally important in fields like computer science, artificial intelligence, and formal reasoning, where expressing complex relationships and facts is crucial for reasoning tasks and knowledge representation.

Other options, while relevant in their respective contexts, do not fulfill the definition provided in the question. Data security and data privacy pertain to protecting information and the rights of individuals regarding their data. A knowledge graph is a way of representing relationships and facts in a structured format, often used in semantic web technologies but is more about the implementation of relationships rather than the logical statements themselves. Therefore, predicate logic is the most accurate term for the logical statements that express facts and relationships.