Final answer:
Set operators like UNION, UNION ALL, INTERSECT, and MINUS are used for combining or excluding data in mathematical sets and database queries. Boolean operators such as AND, OR, and NOT are also applicable in databases and refine keyword searches.
Step-by-step explanation:
The question is about set operators used in both mathematical principles and database query operations. In databases, the UNION operator combines the results of two or more SELECT statements, including duplicates only once.
UNION ALL is similar but includes all duplicates. INTERSECT returns rows that exist in both SELECT statement results. MINUS (or EXCEPT in some databases) shows rows from the first SELECT that do not exist in the second SELECT result.
Implementing Boolean logic in keyword searches involves using AND, OR, and NOT operators. For instance, A AND B includes items found in both sets A and B, whereas A OR B includes any items found in either set.
Using these operators refines searches, much like in databases, allowing retrieval of more precise results. An example could be narrowing down search results to a specific title, author, and publication year utilizing Boolean operators.