The error handling behaviour for WhereClauses containing loops is not clarified in the specification, this should be added.

Consider following filter:
Element0: AND | Element0 | Element 1
Element1: GreaterThan | Severity | 500

This should not be allowed and lead to an error, as this WhereClause leads to an infinite loop.

Consider following filter:
Element0: AND | Element1 | Element2
Element1: Equals | Element3 | 0x10
Element2: Equals | Element3 | 0x20
Element3: BitwiseAnd | Severity | 0x30

This is a very constructed filter but should be allowed to use. Element3 is referenced multiple times but does not lead to an infinite loop, hence the filter should be usable.

Additionally, Part 4 - 7.16.3 - passage 4 says that the WhereClause would use the SimpleAttributeOperand. Instead, also Element- and LiteralOperand may be used, shouldn't that be reflected in this description?