constructed specific symbols manipulated according definite rules work frege simplified amplified alfred north whitehead bertrand russell principia mathematica ''the paradoxes'' time number disturbing paradoxes appeared literature particular burali forti paradox russell paradox richard paradox resultant considerations led kurt g del 's paper specifically cites paradox liar completely reduces rules recursion numbers ''effective calculability'' effort solve entscheidungsproblem defined precisely hilbert mathematicians
Formal science Computer science Algorithms