x_{1} abstractly pertains to an exponential/root/logarithmic relationship between the elements of x_{2} (ordered pair) which are related via concrete relationship x_{3}.

When discussing the so-called 'Triangle of Power' (see, for example: https://youtu.be/sULa9Lc4pck ), this term is useful, as it briefly encapsulates every possible role which the Triangle may denote/act. Each operator (tenfa, fenfa, and dugri) is a binary operator; x_{3} specifies which of these operators is being used (modulo SE conversions), and x_{2} will provide the operands thereof in the order of the inputs given by x_{3}. Notice that lo tenfa, lo fenfa, and lo dugri are all the answers/results of applying the respective operators to an ordered pair of inputs (given by their respective second and third terbri, each); thus, none of these constructs ("lo X") can be submitted to enfa_{3}, which only accepts the operator (not the result of the operator). Either use mekso and mau'au-zai'ai quote the desired VUhU word (te'a, fe'a, or du'o, or their SE conversions), or use a tanru/lujvo in order to create words for "exponentiation operator", "root operator", or "logarithm operator" (or their SE conversions) in order to fill enfa_{3}.

- sau'i
*(exp!)* - mekso n-ary operator: reciprocal of the sum of the reciprocal of each of X
_{1}, X_{2}, ..., X_{n}(for any natural number n); 1/((1/X_{1) + (1/X}.