x1 (text) is a lujvo with meaning x2 and arguments x3, and which is constructed from tanru/veljvo x4 such that each element of the veljvo is ultimately only a cmavo (including "{zei}", "{ke}"/"{ke'e}", "{bo}", etc.), gismu, or rafsi of such cmavo or gismu.
imaginary i, comma - spherical coordinates: first coordinate gives magnitude (complex modulus/radius) of the number, the second number gives the angle from the positive real axis measured counterclockwise toward the 'positive' imaginary axis (default: in the primary branch/Arg) as measured in some units (which that number should contain; the contextless default will suppose radians); the angle is not normalized.
x1 (plural of ordered pairs) is an exhaustive set (possibly infinite) of inputs/outputs defining a unary function which yields result x3 when given input x2; x1(x2) = x3