2.1.11 Implicit Operator

The KQL syntax supports a sequence of expressions (the expression-list element) without any operator between the expressions. In this case, there is an implicit operator between the expressions. The implicit operator is either AND (section 2.1.2) or OR (section 2.1.8). Setting the implicit operator is outside the KQL syntax; it is set through the [MS-SEARCH] protocol.

If the query contains any non-property operator (ALL (section 2.1.1), AND (section 2.1.2), NOT (section 2.1.6), XRANK (section 2.1.10), and so forth), the query MUST be evaluated as if the implicit operator is AND (section 2.1.2).

There are other special cases regarding the use of the implicit operator. See section 2.3.1.1 for the use of the implicit operator in combination with qualified string tokens, and section 2.2.4 for the use of the implicit operator in combination with property restrictions.