AN APPROXIMATE ISOPERIMETRIC INEQUALITY FOR r-SETS
نویسنده
چکیده
We prove a vertex-isoperimetric inequality for [n], the set of all r-element subsets of {1, 2, . . . , n}, where x, y ∈ [n] are adjacent if |x∆y| = 2. Namely, if A ⊂ [n] with |A| = α ( n r ) , then its vertex-boundary b(A) satisfies |b(A)| ≥ c √ n r(n− r)α(1− α) ( n r )
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تاریخ انتشار 2012