 Brouwer, Luitzen Egbertus Jan |  choice, axiom of |  continuity and infinitesimals |  Frege, Gottlob |  Frege, Gottlob: theorem and foundations for arithmetic |  logic: intuitionistic |  mathematics: constructive |  Principia Mathematica |  Quine, Willard van Orman: New Foundations |  Russell’s paradox |  set theory |  type theory 