Which Boolean operator decreases the number of references by requiring a search to contain both of the words or phrases desired?

Both AND and NOT are the Boolean operator that decreases the number of references by requiring a search to contain both of the words or phrases desired. The AND operator needs both the items to be on each item reverted. If one item is not included in the data and the other is not, the item will not be added to the list of results. The OR operator is whichever item (or two) will be in the reverted data.