"valid assumption" is a correct and usable phrase in written English.
You can use it to refer to an assumption that is logical, evident, and reasonable. For example, "It is a valid assumption that increased exercise leads to improved cardiovascular health."
And I think that's a valid assumption for a play.
So is the sun sufficiently bright on Mars for photopic conditions to be a valid assumption?
The dielectric data indicates that 'thermorheologically simplicity' is probably not a valid assumption for this system.
For propagation into mixtures that are sufficiently far from the flammability limit, "quasi-homogeneity" is a valid assumption.
If the size of the piston is small compared to wavelength, then the plane wave excitation is a valid assumption.
Isn't it an equally valid assumption that she might have thought that the short-term suffering caused by her policies would be outweighed by the long-term benefits?
The development of higher strength alloys requiring higher forming forces suggest that a constant friction value may not always be a valid assumption.
This equation assumes that the change in glucose uptake and production induced by a change in plasma insulin is proportional to the ambient insulin concentration, which may not be a valid assumption at maximal insulin concentration18.
This strategy allows to activate mixed mode criteria for delamination initiation which is a valid assumption for laminates with layers of different orientations.
In the paper we assume the crack band elements of constant width throughout the analysis, which may be a valid assumption at high temperatures, as indicated by some data given in literature.
This is usually a valid assumption.
