  We consider a new semidefinite programming (SDP) relaxation of the symmetric
traveling salesman problem (TSP) that may be obtained via an SDP relaxation of
the more general quadratic assignment problem (QAP). We show that the new
relaxation dominates the one in [D. Cvetkovic, M. Cangalovic, and V.
Kovacevic-Vujcic, Semidefinite programming methods for the symmetric traveling
salesman problem, in Proc. 7th Int. IPCO Conference, Springer, London, 1999,
pp. 126--136]. Unlike the bound of Cvetkovic et al., the new SDP bound is not
dominated by the Held-Karp linear programming bound, or vice versa.
