In a standard subdivision, 60percentt of the buildable land must be left as open space, and houses must be clustered on the remaining 40percentt, which must also be used for roads and drainage.
These questions are left as open research questions for future research.
Since the Vertex Coloring Problem is a particular case of Weighted Coloring, it is obvious that the complexity of this problem in the weighted case is as hard as in the non-weighted one and can also be left as open question.
At this stage that possibility is left as an open question, but it is important to notice that for it to be an open question we need to at least allow for a distinction between events and the ways in which they are picked out in language.
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.
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, a number of unknown bacterial strains had been injected into the reservoir in that study, and it is unclear which bacteria had caused the decrease in viscosity, so the reproducibility of the effects was left as an open question.
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]).
