The phrase "a problem on which" is correct and usable in written English.
It can be used when discussing a specific issue or topic that is the focus of attention or analysis.
Example: "This is a problem on which we need to focus our efforts to find a solution."
Alternatives: "a problem that we need to address" or "an issue we should consider."
Yet when it comes to identifying what he taught and believed, there is a problem, on which Bill & Ted's Excellent Adventure, rather unexpectedly, puts its finger.
Armstrong's classic researches in chemistry dealt in part with subsitution in the hydrocarbon naphthalene, a problem on which he published some 60 treatises, which, with the work of his collaborators, securely established the chemistry of a substance and its derivatives that were of the greatest technical importance in the dyestuffs industry.
Donald Trump's Presidency has been so partisan and circumscribed — so concentrated in Washington, and on the defense of orthodox Republican ideas and the settling of petty feuds — that it is unusual to see Trump in the more mundane position required by the opioid epidemic, picking his way through a problem on which neither party has a clear view and about which we are still gathering evidence.
Access to healthy and affordable foods in low-income communities and rural communities, where the obesity epidemic is quite severe, is a problem on which all of us should be focused.
Constructing synteny blocks from fragmented assemblies raises a problem: on which scale should synteny blocks be constructed?
In the third experiment we wanted to apply the method on a real problem on which we had no previous assumption.
The designer also needs to determine a similar problem on which the modeling can be based.
But the huge personal indebtedness of Haitians is a largely hidden problem, on which no one is campaigning.
This paper introduces the very first formal representation of BPA by means of an optimisation problem, on which to base the next generation of crime reconstruction techniques.
CU splitting is modeled as a binary classification problem, on which a support vector machine (SVM) is applied.
But if he wants to leave his post on a heroic note, he could readily do so by turning his attention to a different, longstanding problem on which he has been stubbornly retrograde -- the overdue need to cleanse the Hudson River of PCB's.
