Nondifferentiable variational principles in terms of a quantum operator
  We develop Cresson's nondifferentiable calculus of variations on the space of H\"{o}lder functions. Several quantum variational problems are considered: with and without constraints, with one and more than one independent variable, of first and higher-order type. 
Ricardo Almeida, Delfim F. M. Torres
math.OC math-ph math.MP