 -->Cantor, Georg--> |  Frege, Gottlob |  Frege, Gottlob: theorem and foundations for arithmetic |  logic: paraconsistent |  mathematics: inconsistent |  -->Peano, Giuseppe--> |  Principia Mathematica |  Quine, Willard van Orman: New Foundations |  Russell, Bertrand |  self-reference |  type theory |  Whitehead, Alfred North 