We will often use variational optimization. When the variational family is not made explicit it means that the optimization is over all functions with the correct domain and codomain, e.g.
Automatic bidding has become one of the main options for advertisers to buy advertisement opportunities in the online advertising market [Dolan, 2020].
Automatic bidding has become one of the main options for advertisers to buy advertisement opportunities in the online advertising market [Dolan, 2020].