= Solution
\b[Not automatically: the duplicate-value policy must implement a <multiset>.] A strict <binary search tree> storing one entry per distinct key represents a <set>; inserting a second equal value then loses a required occurrence. A fixed rule that puts all equal values on one side also needs care, because ordinary balancing rotations need not preserve that one-sided equality rule.
One valid refinement stores a multiplicity at each distinct key. Inserting an equal key increments its count; `delMin` decrements the minimum key's count and removes that node only at zero. Alternatively, use distinct internal keys such as `(value, uniqueSerial)` while ordering primarily by value and returning only the value. With an appropriate balanced representation either approach preserves every occurrence and the required operation bounds. A bare claim about balanced search trees, with no treatment of duplicates, does not establish the abstract specification.
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