Linked from
The 18 pages that link to Objective function, each with the reason it gives.
Gradient descentRelated: The method repeatedly changes parameters to lower this function.
Constrained optimizationRelated: Its values determine which feasible point counts as best.
Assignment problemRelated: Summing the selected pairing costs gives the objective to minimize.
Mathematical optimizationRelated: It quantifies what optimization seeks to maximize or minimize.