fe'au'u VUhU3 experimental cmavo

mekso ternary operator: positive super-root; the bth super-root (inverse operator of hyper-operator with respect to base) of a of order c-2.

c must be nonnegative (and currently must also be an integer). c=3 yields the basic/typical bth root function on a (undoes exponentiation); c=4 yields the bth sroot (undoes tetration). In conventional English notation (not necessarily Lojbanic), this is the right-inverse on the same-order hyperoperator. See: dei'au'o, te'au'u, de'au'u

In notes:

de'au'u
mekso ternary operator: positive super-logarithm; the super-logarithm (inverse operator of hyper-operator with respect to "height" of power tower) of a with base b and of order c-2.
te'au'u
mekso ternary operator: Knuth up-arrow notation: a \uparrow \dots \uparrow b of order/with c-2 arrows ("\uparrow") initially, evaluated from right to left; the cth hyperoperator on a by b.