number > number theory > algebraic number theory > modular arithmetic > Lagrange's four-square theorem

geometry > algebraic geometry > Diophantine geometry > Diophantine equation > Lagrange's four-square theorem

number > number theory > Diophantine geometry > Diophantine equation > Lagrange's four-square theorem

... > mathematical analysis > function > elementary function > polynomial > polynomial equation > Diophantine equation > Lagrange's four-square theorem

algebra > polynomial > polynomial equation > Diophantine equation > Lagrange's four-square theorem

mathematical analysis > equation > polynomial equation > Diophantine equation > Lagrange's four-square theorem

number > number theory > analytic number theory > additive number theory > Lagrange's four-square theorem