A descriptor is a designator which is a conceptual graph. The conceptual graph is said to describe the referent.
Here is an example:
[PartyLight: [PartyLight]->(Chrc)->[Color: Blue] ]- <-(Agnt)<-[Blink] "There is a party light, which can be described as a partylight having a characteristic which is a color which is blue, and the party light is the agent of blink.". "A blue party light is blinking."
[Proposition: [Man: ]->(Attr)->[Mortal] ] "There is a proposition, which is 'All men are mortal'"
As we see, the conceptual graph
fills the slot of the referent of the concept with the type "Proposition". This conceptual graph is the descriptor.
A blank designator is taken as a descriptor which is a blank conceptual graph. Thus it says nothing about the referent.
Blank designator, blank quantifier
If both the quantifier and the designator are blank, it simply means "There is a", e.g.:
[Cat] "There is a cat" [Mortal] "There is a property, Mortal"
Blank designator, non-blank quantifier
We can also have a non-blank quantifier with a blank designator:
[Man: ] "All men" [Number: @18] "There are 18 numbers"
Here, the quantifier is "" and "@18" respectively, while the designator is a descriptor which is a blank conceptual graph.
Next, we give a summary which will hopefully help you get the big picture of referents.
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Up: 9.9 Referents (optional)
Next: 9.9.6 Summary