CONTENTS
Preface
iii1 Gaussian measures on Hilbert spaces 1
1.1 Borel measures on Hilbert spaees . . . . 1 1.2 Gaussian measures on Hilbert spaees . . . . 8 1.3 The Hellinger integraI and the Cameron-Martin theorem 16
2 Heat equations in Hilbert spaces 25
2.1 Construetion of the heat semigroup . . . 28
2.2 Regularity of the heat semigroup 31
2.3 Solutions of
(H E)and eharacterization of the generator of (Pd
392.4 The speetrum of the infinite dimensionaI Laplacian 42
3 The Omstein-Uhlenbeck semigroup 45
3.1 The Ornstein-UhIenbeek semigroup on Cb(H) 46 3.2 SoboIev spaees with respeet to Gaussian measures on H . . . 49 3.3 The Ornstein-UhIenbeek semigroup on LP-spaees with invari-
ant measure . . . 55 Appendix
A.1 The classical Boehner theorem . A.2
Co-semigroups .. . . . Bibliography
73 73 77
81