n-ary mekso operator: for an input of ordered list of ordered pairs ((X_{1, Y}, it outputs formal generalized rational function (x - X_{1)^Y} in the adjoined indeterminate (here: x).

n may be infinite, under the condition that the function is well-defined. In the definition, adjacency of terms denotes multiplication in the relevant algebraic structure. If there is an i such that Y_{i} is omitted, then Y_{i }= 1 by default. For any i, there is no constraint on the values which may be taken by X_{i} or Y_{i}. See also: "po'i'oi".

- po'i'oi
*(exp!)* - mekso at-most-3-ary operator: convert to polynomial; X
_{1}(ordered list of algebraic structure (probably field) elements) forms the (ordered list of) coefficients of a polynomial/Laurent-like series with respect to indeterminate X_{2}under ordering rule X_{3}(default for finite list: the first entry is the coefficient of the highest-degree term and each subsequent entry is the next lesser-degree coefficient via counting by ones and wherein the last entry is the constant term) - cpolinomi'a
- x
_{1}is a formal polynomial with coefficients x2 (ordered list) of degree x_{3}(li; nonnegative integer) over structure/ring x_{4}(to which coefficients x_{2}all belong) and in indeterminant x_{5}.