function h = dtreehijub(A,C,T,m,n,i,j)

dpi = dpath(T,1,i);
dep_i = length(dpi)

%[dp,j0] = dpath(T,i,j);
%if ~j0
%    h = 1e-9;
%    return
%end
%dpj = dpath(T,1,j0);
%dep_j = length(dpj)

dpj = dpath(T,1,j);
dep_j = length(dpj)

%if dep_i > dep_j
%    keyboard
%end

[w,levels,ll] = treewidth(T);

h = 1;
for d = dep_i+1:dep_j
  levd = levels{d};
  thh = [];
  for v = levd
    u = find(T(:,v));
    Auv = reshape(A(u,v,:,:),[m m]);
    thh(end+1) = gettha(Auv);
  end
  h = h * inclexcl(thh);
end
return

function th = gettha(A)
[n,n] = size(A);
th = 0;
for i=1:n
  for j=i+1:n
    x = A(:,i);
    y = A(:,j);
    d = .5*sum(abs(x-y));
    if d>th
      th=d;
    end
  end
end
return



function [dp,j0] = dpath(T,i,j)
% bounds hh(i,j) for a tree

% find j0, where
% j0 is the minimum descendant of i s.t. j0>=j


Ti = getSubt(T,i);

jj = Ti(Ti>=j);
if isempty(jj)
  dp = [];
  j0 = 0;
else
  j0 = min(jj);
  dp = parentseq(T,j0,i);
end
return

function pseq = parentseq(T,u,r)
v = u;
el = 0;
pseq = [u];
while v~=r
  el = el+1;
  rents = find(T(:,v));
  v = rents;
  pseq = [v pseq];
end
return



function sT = getSubt(T,v)
% a list of v's descendents in T
% includes v itself
global SUBT
SUBT = [];
Pi(T,v);
sT = SUBT;
return

function Pi(T,v)
global SUBT
SUBT(end+1) = v;
vkids = find(T(v,:));
for vi=1:length(vkids)
  v1 = vkids(vi);
  Pi(T,v1);
end