%0 Journal Article %T Euclidean Quantum Gravity in Light of Spectral Geometry %A Giampiero Esposito %J Mathematics %D 2003 %I arXiv %X A proper understanding of boundary-value problems is essential in the attempt of developing a quantum theory of gravity and of the birth of the universe. The present paper reviews these topics in light of recent developments in spectral geometry, i.e. heat-kernel asymptotics for the Laplacian in the presence of Dirichlet, or Robin, or mixed boundary conditions; completely gauge-invariant boundary conditions in Euclidean quantum gravity; local vs. non-local boundary-value problems in one-loop Euclidean quantum theory via path integrals. %U http://arxiv.org/abs/hep-th/0307226v1