Definition of "r" []

• The 18th letter of the modern English alphabet. (noun)
• Any of the speech sounds represented by the letter r. (noun)
• The 18th in a series. (noun)
• Something shaped like the letter R. (noun)
• Radius (abbreviation)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "An uncharged black hole has no inner horizon; it should come as no surprise, then, that as you increase the charge (keeping the mass of the black hole fixed), the two horizons at r+ and r - come together."
• "In an extremal black hole, where all of the energy comes from the electric field itself, the two horizons coincide: we have r+ = r - (extremality)."
• "A representation r is maximally consistent if and only if r is consistent and for any representation r², either r & not-r² is not consistent or r & r² is not consistent (assuming the appropriate conceptions of the negation and conjunction of representations)."