On August 13, 2009, Paul Tseng went missing while kayaking in the Jinsha River in the Yunnan province of China and is presumed dead.

[2] Tseng made many contributions to mathematical optimization, publishing many articles and helping to develop quality software that has been widely used.

[4] Furthermore, together with Tom Luo, he resolved a long-standing open question on the convergence of matrix splitting algorithms for linear complementarity problems and affine variational inequalities.

[6] Tseng has coauthored (with his Ph.D. advisor, Dimitri Bertsekas) a publicly available network optimization program, called RELAX,[7] which has been widely used in industry and academia for research purposes.

On August 13, 2009, Paul Tseng went missing while kayaking in the Yantze river near Lijiang, in Yunnan province of China and is now presumed dead.