function A = sauer_inc ( )

%*****************************************************************************80
%
%% sauer_inc() sets up the incidence matrix associated with a network.
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    12 September 2024
%
%  Author:
%
%    John Burkardt
%
%  Reference:
%
%    Timothy Sauer,
%    "How search engines rate page quality",
%    Numerical Analysis,
%    Pearson, 2006.
%    ISBN: 0-321-2698-9,
%    LC: QA297.S348
%
%  Output:
%
%    real A(15,15): a sparse incidence matrix.
%
  A = [ ...
     0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0 ; ...
     0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0 ; ...
     0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0 ; ...
     0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0 ; ...
     1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0 ; ...
     0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0 ; ...
     0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0 ; ...
     0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0 ; ...
     0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0 ; ...
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0 ; ...
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 ; ...
     0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0 ; ...
     0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0 ; ...
     0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1 ; ...
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0 ];

  return
end
