Previously, I'd seen leaving as a problem.
It is, therefore, left as an open problem.
Proving that mixed tuples indeed get a score below η is left as an open problem.
But, its analytic proof as attempted by Eq. (9.3) cannot be made, thus being left as an open problem.
It was also left as an open problem to extend the framework to incorporate more attacks namely the slide, boomerang, amplified boomerang/rectangle and Square attacks.
The exact EIS computation was left as an open problem in [5] and has attracted a great deal of attentions in recent years (see, e.g., [9]-[11],[13],[15],[16]).
However, how to evaluate the expected influence propagation for selecting the nodes with the maximum marginal gain was left as an open problem, and the greedy algorithm in [14] was implemented by Monte Carlo (MC) simulation.
In [5], how to compute the exact marginal gain (i.e., compute the EIS increment when adding a node) under the two models was left as an open problem, and they estimated it by running the Monte Carlo (MC) simulation, which is not computational efficient (e.g., it takes days to select 50 seeds in a moderate size graph of 30K nodes [11]).
An interesting direction for future research is the consideration of frequency-selective channels and of frequency synchronization. 1 The more general case with spectral aliasing could be handled by using the analysis in [17] and is left as an open problem.
The question whether it is possible to deal with such an adversary and to design protocols that would discover routes which avoid traffic jams so that nodes only store a bounded number of packets was left as an open problem by Andrews et al. (1997, in "Proc. of 38th FOCS," pp. 294 302) (who deal with the nonadaptive case where the adversary provides routes for the packets).
