A better model of deferral 
Wednesday, April 27, 2011
4:09 PM
A deferred subtraction is not an action, but rather, a binding. 
It says: from now on, return for the value of x, 
the things that are in x but not in y. 
No matter how y changes. 
You can bind multiple sets to x. 
Note that: 
you cannot subtract an element from a set. 
You can bind sets together, so that the binding implements a subtraction, 
while both sets are computed via monotonic logic!