Treffer: Bilevel fractional programming; Combinatorial matrix analysis; Combinatorial optimization algorithms in resource allocation problem; Combinatorial optimization games; Complexity classes in optimization; Complexity of degeneracy; Complexity of gradients, Jacobians, and Hessians; Complexity theory; Complexity theory: Quadratic programming; Computational complexity theory; Evolutionary algorithms in combinatorial optimization; Fractional programming; Information-based complexity and information-based optimization; Kolmogorov complexity; Mixed integer nonlinear programming; Multi-objective combinatorial optimization; Neural networks for combinatorial optimization; NP-complete problems and proof methodology; Parallel computing: Complexity classes; Quadratic fractional programming: Dinkelbach method; Replicator dynamics in combinatorial optimizationBilevel fractional programming; Combinatorial matrix analysis; Combinatorial optimization algorithms in resource allocation problems; Combinatorial optimization games; Complexity classes in optimization; Complexity of degeneracy; Complexity of gradients, Jacobians, and Hessians; Complexity theory; Complexity theory: Quadratic programming; Computational complexity theory; Evolutionary algorithms in combinatorial optimization; Fractional programming; Information-based complexity and information-based optimization; Kolmogorov complexity; Mixed integer nonlinear programming; Multi-objective combinatorial optimization; NP-complete problems and proof methodology; Parallel computing: Complexity classes; Quadratic fractional programming: Dinkelbach method; Replicator dynamics in combinatorial optimization; Stochastic integer programsFRACTIONAL COMBINATORIAL OPTIMIZATION: FCO