Individual km#modal_logic__intensional_logic__intensionallogic  sentences are qualified by modalities such as possibly and necessarily; both "Bush is president" and "2+2=4" are true, yet "Necessarily, Bush is president" is false, while "Necessarily, 2+2=4" is true
  >part of:  formal_logic
  url:  http://en.wikipedia.org/wiki/Modal_logic  http://plato.stanford.edu/entries/logic-modal/
  >part:  deontic_logic__deonticlogic
  >part:  epistemic_logic__epistemiclogic
  >part:  temporal_logic  system of rules and symbolism for representing, and reasoning about, propositions qualified in terms of time
     >part:  tense_logic__tenselogic
     >part:  computational_tree_logic__CTL
     >part:  linear_temporal_logic
  >part:  conditional_logic__conditionallogic

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