+ 14. Someone^x is in the closet who_x might be guilty.
+
+ {(w,0,r,g), (w',0,r,g)}[∃x(closet(x) & ◊guilty(x))]
+
+ -- existential introduces new peg
+
+ = {(w,1,r[x->0],g[0->b])}[closet(x)][◊guilty(x)]
+ ++ {(w,1,r[x->0],g[0->c])}[closet(x)][◊guilty(x)]
+ ++ {(w,1,r[x->0],g[0->d])}[closet(x)][◊guilty(x)]
+ ++ {(w',1,r[x->0],g[0->b])}[closet(x)][◊guilty(x)]
+ ++ {(w',1,r[x->0],g[0->c])}[closet(x)][◊guilty(x)]
+ ++ {(w',1,r[x->0],g[0->d])}[closet(x)][◊guilty(x)]
+
+ -- filter out possibilities in which x is not in the closet
+ -- and filter out possibilities in which x is not guilty
+ -- the only person who was guilty in the closet was Dave in
+ -- world 1
+
+ = {(w,1,r[x->0],g[0->d])}
+
+The result is different, and more informative.
+
+## Binding, modality, and identity
+
+The fragment correctly predicts the following contrast:
+
+ 15. Someone^x entered. He_x might be Bob. He_x might not be Bob.
+ (∃x.enter(x)) & ◊x=b & ◊not(x=b)
+ -- This discourse requires a possibility in which Bob entered
+ -- and another possibility in which someone who is not Bob entered
+
+ 16. Someone^x entered who might be Bob and who might not be Bob.
+ ∃x (enter(x) & ◊x=b & ◊not(x=b))
+ -- This is a contradition: there is no single person who might be Bob
+ -- and who simultaneously might be someone else
+
+These formulas are expressing extensional, de-reish intuitions. If we
+add individual concepts to the fragment, the ability to express
+fancier claims would come along.
+
+### Identifiers
+
+Let α be a term which differs from x. Then α is an identifier if the
+following formula is supported by every information state:
+
+ ∀x(◊(x=α) --> (x=α))
+
+The idea is that α is an identifier just in case there is only one
+object that it can refer to. Here is what GSV say:
+
+ A term is an identifier per se if no mattter what the information
+ state is, it cannot fail to decie what the denotation of the term is.
+
+## Why articulate the mapping from variables to objects into two
+ parts?
+
+In the current system, variables are associated with values in two
+steps.
+
+ Variables Pegs Entities
+ --------- r ---- g --------
+ x --> 0 --> a
+ y --> 1 --> b
+ z --> 2 --> c
+
+Here, r is a refsys mapping variables to pegs, and g is an assignment
+function mapping pegs to entities.
+
+Assignment functions are free to map different pegs to the same
+entity: