The phrase "are prohibitively difficult to" is correct and usable in written English.
It can be used to describe something that is extremely challenging or impossible to achieve or accomplish.
Example: "The tasks required for this project are prohibitively difficult to complete within the given timeframe."
Alternatives: "are excessively hard to" or "are unreasonably challenging to".
A high minimum wage 60% of the average blue collar wage, according to the OECD means companies are reluctant to take on employees who are prohibitively difficult to shed.
These matrices are prohibitively difficult to acquire due to the different geometries required during imaging, as well as the complex wavelength and angular response of commercial wave plates.
The electrical activity on the heart surface during VF has been recorded extensively in the experimental setting and in some cases clinically; however, corresponding transmural activation patterns are prohibitively difficult to measure.
But lights are cumbersome and time-consuming to set up, and outside the studio, it can be prohibitively difficult to position them where, ideally, they ought to go.
That's the defining difference between the US and British systems: in America, it's prohibitively difficult to overturn a supreme court decision.
America has usually steered clear of this sort of action against state-run economies, saying it is prohibitively difficult to calculate excess subsidies.
The main contributions of MAGNIFY are that it provides new and complex parallelization strategies that would be prohibitively difficult to implement by hand, and that it allows the programmer to determine their use.
Without the plumes, it would be prohibitively difficult to sample and observe Europa's ocean, but their presence gives scientists a chance to conduct these experiments on ocean material that is being ejected into space.
Somewhat akin to Heisenberg's uncertainty principle, it is prohibitively difficult to make high-resolution measurements during VF without disturbing the natural behaviour.
Synaptic integrity is a strong indicator of cognitive health in the human brain;however, until recently, it was prohibitively difficult to perform detailed analyses of synaptic and axonalstructure in human tissue sections.
Potential limitations of the study include the use of a sibling design instead of a twin design; the latter would have allowed the disentangling of genetic from environmental influences, but it would have been prohibitively difficult to complete.
