Linked from

The 2 pages that link to Titu's lemma, each with the reason it gives.

• Nesbitt's inequalityRelated: Setting each aᵢ to 1 and bᵢ to x, y, z bounds the reciprocal sum.

• Shapiro inequalityRelated: Its fraction-sum form is a common first tool when bounding sums of cyclic ratios.