“We show that some known classical results have particularly simple derivations within the Ashtekar formalism. These include Witten's positive energy theorem…”
"Positive energy in quantum gravity" arXiv (Jun 10, 2014)
Help us to complete the source, original and additional information
Lee Smolin 52
American cosmologist 1955Related quotes

"Energy and Force" (Mar 28, 1873)

spiegel.de http://www.spiegel.de/international/europe/spiegel-interview-with-ecb-president-mario-draghi-a-941489.html.
Set theory and the continuum hypothesis, pp. 19–20 https://books.google.com/books?id=Z4NCAwAAQBAJ&pg=PA19
Set Theory and the Continuum Hypothesis (1966)

"Energy and Force" (Mar 28, 1873)
“The idea that theorems follow from the postulates does not correspond to simple observation.”
The Unreasonable Effectiveness of Mathematics (1980)
Context: The idea that theorems follow from the postulates does not correspond to simple observation. If the Pythagorean theorem were found to not follow from the postulates, we would again search for a way to alter the postulates until it was true. Euclid's postulates came from the Pythagorean theorem, not the other way around.