(exobiology) A formula for calculating the probability of civilizations existing elsewhere in the Milky Way galaxy and of their ability to communicate with Earth.

plural of differential equation

(chemistry) Either of two equations that describe each half of a redox reaction

(physics) A relativistic wave equation that describes an electron (and similar particles); it predicted the existence of antiparticles

(mathematics) A polynomial equation whose greatest exponent is 3.

plural of linear equation

(mathematics) A polynomial equation of the first degree (such as x = 2y - 7)

(number theory) A polynomial equation whose variables are only permitted to assume integer values.

plural of Diophantine equation

(mathematics) An equation involving a function f(x) and integrals of that function to be solved for f(x)