The minimum number of incomplete blocks required to cover, exactly \(A\) times, all \(t\)-element subsets from a set \(V\) of cardinality \(v\) (\(v \geq t\)) is denoted by \(g(\lambda,t;v)\). The value of \(g(2,2;v)\) is known for \(v = 3, 4, \ldots, 11\). It was previously known that \(14 \leq g(2, 2; 12) \leq 16\). We prove that \(g(2,2;12) \geq 15\).
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