Prove that by the Cauchy-Schwarz inequality, we have
i=1∑n1−∣xi∣n1⋅i=1∑n(1−∣xi∣n)⩾n2.
Therefore, to prove the original inequality, it suffices to prove
That is, to prove □□
∑i=1n(1−∣xi∣n)n2⩾1−∏i=1nxinn−n∏i=1nxi⩾∑i=1n(1−∣xi∣n)∑i=1n∣xi∣n⩾n∏i=1nxi
That is, □
By the AM-GM inequality, the above inequality holds, hence the original proposition is true.