home.md

@@ -28,6 +28,11 @@ bitwise logic and shifting.
 Parabix programs are assembled as sequences of kernels operating on stream sets.   Kernels are generally
 just functions, taking stream sets as input and producing stream sets as output.    
 
+From a programmer's point of view, kernels can often be viewed as pure mathematical functions defined
+over stream sets.   Some kernels are side-effecting, achieving computational results by calling back
+to standard C++ programs, for example.    But many kernels have a pure mathematical result, in which
+the only effect is the set of output streams produced in response to the given input streams.
+
 ## Parabix Transform 
 
 The Parabix framework is based on the concept of parallel bit streams,