The phrase "assuming the existence" is correct and usable in written English.
It can be used when discussing a hypothetical situation or premise that relies on the acceptance of something's existence.
Example: "Assuming the existence of extraterrestrial life, we must consider the implications for our understanding of the universe."
Alternatives: "presuming the existence" or "taking for granted the existence".
Nevertheless, the fact that there existed this range of possible explanations all assuming the existence of atoms can be seen as constituting evidence for atoms by those favouring inferences to the best explanation.
Proposition 1. Assuming the existence and the uniqueness of the minimizer for the functional (2.1), there exists a complementary variational principal for (2.1).
Psychographic segmentation ignores this complexity by assuming the existence of one hat that fits all occasions.
Assuming the existence of an eighth planet in the solar system solved that problem nicely.
The theory explained combustion by assuming the existence of a hypothetical substance, phlogiston, that left a material as it burned.
Even assuming the existence of a politically neutral way to mark certain messages as unworthy of archiving, this seems like a really bad idea to me.
Here we have studied the dynamics of consensus building on relatively short within-generational time scales while assuming the existence of certain within-group variation.
(c) The 3D SHG polarimetry has been calculated assuming the existence of a planar ferroelectric polarization oriented either parallel (Bloch) or perpendicular to the walls (Néel).
Dynamic contact lines are handled by assuming the existence of a thin precursor film near the stream edges.
In this paper we partially break this interdependence by assuming the existence of landmark regions in the workspace.
Assuming the existence of a large quantity of extra mass neatly explains away the behaviour of the universe on very large scales.There is another possibility, of course.
