- When an <ref target="OrderedAggregation">Ordered Aggregation</ref> <ref target="hasSlot">has a slot</ref>, its index must be unique within that Ordered Aggregation.
- However, Slots are permitted to <ref target="ore:proxyIn">be proxies in</ref> other kinds of <ref target="ore:Aggregation">Aggregation</ref>, in which case index uniqueness is not required.
- </p>
- <p>
- When a Slot <ref target="olo:ordered_list">has an ordered list</ref>, its index should be less than or equal to the <ref target="olo:length">length</ref> of that <ref target="olo:OrderedList">Ordered List</ref>.