Perhaps unfortunately, the stress of the Lojbanized name falls on the final syllable ("tis"); this version enunciates the /t/, rather than reducing it to a tap.
binary mekso operator: Let the inputs X1 and X2 be sets in the same universal set O; then the result of this operator applied to them is X1^c
\cup X, where for any A \subseteq O, Ac = O \setminus A.