lecture notes in logic - UCLA Department of Mathematics
... Together with (2), this means that for all x, y in K,
x · y = 0 ⇐⇒ x = 0 or y = 0.
(4) For all x, y, z, x · (y + z) = x · y + x · z (the distributive law ).
Basic examples of fields are the rational numbers Q, the real numbers R
and the complex numbers C, with universes Q, R, C respectively and the