Footprints, Delta, and Subtraction

With interaction surfaces in place, we can define how a thing affects the semantic field and how to compare or remove that influence.

Footprint

The footprint of a thing is the closure of its thing fragment using the state’s operators. It yields a closed partial state associated with the thing.

Delta

Delta measures difference between interaction surfaces, fragments, or footprints. It captures how much two things diverge in their semantic effects.

Subtraction

Subtraction removes semantic influence. It is defined using Heyting subtraction and fragment generation so that removal stays inside the closure discipline.