Stephen Hawking Quotes about Boundaries
Stephen W. Hawking (2003). “The Illustrated Theory of Everything: The Origin and Fate of the Universe”, New Millenium
The boundary condition of the universe is that it has no boundary.
Stephen Hawking, Roger Penrose (2010). “The Nature of Space and Time”, p.79, Princeton University Press
"The Anthropic Cosmological Principle". Book by John D. Barrow, Frank J. Tipler, 1986.