why is a dual function concave why is an infimum concave why is the lagrangian function concave why is a dual function concave what is the infimum over the family of affine functions why is the lagrangian function concave why is it concave? which function is concave? which function does the lagrangian infimum over? why is a dual function concave? what is infimum function why is g concave why is infimum concave what is the infimum function? why is the function f_0 concave concave affine function definition which condition of the lagrangian is true for the infimum function what is infimum is the infimum relative which function is concave