Maximum Principle for Parabolic Inequalities and the Heat Flow on Open Manifolds Jozef Dodziuk Indiana University Mathematics Journal 1983 text pdf 10.1512/iumj.1983.32.32046 10.1512/iumj.1983.32.32046 en Indiana Univ. Math. J. 32 (1983) 703 - 716 state-of-the-art mathematics http://iumj.org/access/