ABSTRACT
Theorem 1. For g a function on a cell K the differential dg is continuous at a point p in K if and only if the function g is continuous at p.
A more general result is the following.
Theorem 2. Let σ = [5] be a differential on a cell K and p be a point in K . Then 1ρσ = 0 if and only if S (I,p ) —> 0 as (I ,p ) —► p in K .