PM-FLT-0060

A Filter's proposition MUST hold when there exists at least one instance in the Object State and, where the Subject and predicate positions are filled, at least one instance in the Subject State related to it by the predicate. An implementation MUST NOT read a Filter universally, and MUST NOT require the Subject-side relation to be total.

Where a Filter fills only the Object position, the proposition MUST hold when there exists at least one instance in the Object State.

Non-normative. This is the SOME row of the table in the withdrawn PM-FLT-0040, and it resolves that assertion's four readings down to one. The description states it for the Component case at PAT:us9378071b2#para-2014 and for the Object-model case at PAT:us9378071b2#para-2013: "the Filter defines that in case any instance which has the state defined as Object is true an Operation is going to be enabled".

Two consequences worth stating. Existential quantification means a Filter can never be falsified by adding data, only satisfied — so Filters are monotone in the instance graph, and a transition once enabled stays enabled until the underlying States change. And the vacuity question that dogged the EVERY reading does not arise: an empty relation simply fails the Filter.

What remains open is whether a modeller may ask for another quantifier. The description gives the engine's behaviour, not the notation's expressive limit, and pciml:Filter as described carries no quantifier slot to put one in. That is now a narrower question than Q-G-0003 asked, and it is recorded as Q-G-0031.