XSLT 2.0 and XPath 2.0 Programmer's Reference, 4th Edition (448 page)

The following table compares simple mapping expressions with
for
expressions and path expressions:

The
some
and
every
Expressions

These expressions are used to test whether some item in a sequence satisfies a condition, or whether all values in a sequence satisfy a condition.

The syntax is:

Expression	Syntax
QuantifiedExpr	( some | every ) $ VarName in ExprSingle ( , $ VarName in ExprSingle)* satisfies