Products of Two Involutions in the General Linear Group Frederick HoffmanEugene Paige Indiana University Mathematics Journal 1971 text pdf 10.1512/iumj.1971.20.20096 10.1512/iumj.1971.20.20096 en Indiana Univ. Math. J. 20 (1971) 1017 - 1020 state-of-the-art mathematics http://iumj.org/access/