8-ary mekso operator: the X_{1}th nonnegative sum of X_{2} mutually-distinct perfect X_{3}th-powers (i.e.: of integers) in X_{4} mutually truly-distinct ways, requiring exactly X_{5} terms to be negative in each sum (counting with(out^X_{6}) multiplicity), requiring exactly X_{7} terms to be repeated between sums (counting with(out^X_{8}) multiplicity), according to the usual ordering of the integers.

By default, X_{1 }= 1, X_{5 }= X_{6 }= X_{7 }= X_{8 }= 0. Use "su'e" in X_{5} or X_{6} for weaker but bounded criteria (this will 'cancel' the corresponding "exactly"). For i being 6 or 8, if X_{i} is even, then "with multiplicity" is meant in the corresponding clause/requirement which is governed by this parameter; else, X_{i} is to be odd and "without multiplicity" is meant there. 0 is a valid summand and may be used multiple times. "Truly-distinct ways" in this context includes meanings such as "ignoring both parenthesis/priority and commutation/permutation of terms".