In this paper, we discuss some properties of Block Feedback Neural Net
works (BFN). In the first part of the paper, we study network structur
es. We define formally what a structure is, and then show that the set
F-n of n-layers BFN structures can be expressed as the direct sum of
the set A(n) of n-layers BFN architectures and the set D-n of n-layers
BFN dimensions. Both A(n) and D-n are shown to have the structure of
a distributive lattice and to indice such structure in F-n. Moreover,
we show that the computing capabilities of BFN are monotonically nonde
creasing with the elements of A(n) ordered according to the lattice st
ructure. In the second part we show that the increasing in the computi
ng power allows the BFN to be universal computers, having the same com
puting power as a Turing machine.