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