function L = graph_arc_petersen ( )

%*****************************************************************************80
%
%% graph_arc_petersen() sets up the arc list for the Petersen graph.
%
%  Discussion:
%
%    The graph has 10 nodes and 15 arcs.
%
%  Licensing:
%
%    This code is distributed under the MIT license. 
%
%  Modified:
%
%    25 April 2026
%
%  Author:
%
%    John Burkardt
%
%  Output:
%
%    integer arc(15,2): the arc list.  
%
  L = [ ...
    1,  2; ...
    1,  5; ...
    1,  6; ...
    2,  3; ...
    2,  7; ...
    3,  4; ...
    3,  8; ...
    4,  5; ...
    4,  9; ...
    5, 10; ...
    6,  7; ...
    6, 10; ...
    7,  8; ...
    7, 10; ...
    8, 10]

  return
end
