The phrase 'the key notion' is correct and usable in written English.
You can use it when you want to refer to a central or important idea. For example, "The key notion of this book is that we are all connected."
The key notion now is energy.
The heart of Frege's logical revolution was his treatment of the key notion of generality.
The key notion in all this is that of the dhammas.
Philosophical questions concerning this topic were debated in the 3rd to 5th centuries, as noted above, in terms of the key notion of ousia/substantia.
"In the American press after Dunblane," says Glassner, "the key notion was this just shows that gun control does nothing because Britain has the strictest, whereas in Britain the response was: we need to close this loophole".
An important contribution to epistemology was made by the writers on the Yoga: this concerns the key notion of vikalpa, which stands for mental states referring to pseudo-objects posited only by words.
This is especially the case with some of the key notions discussed by Mr. Aczel, namely the continuum hypothesis and the axiom of choice.
This paper studies the execution semantics of modern distributed SPEs focusing on the key notions of time and windows.
"The key notions related to foresight are policy making, public participation, learning, alternatives, complex socio-technical systems, and science-society relationships" [5].
In this paper, we carry on with the analysis of constructible concepts initiated in [M. Freund, On the notion of concept 1. Artificial Intelligence 172 (2008) 570 590], and examine the key notions of categorization theory that are linked with category-based induction.
Nevertheless, there is some evidence that Nāgārjuna two main aims were something else: firstly, to reject a substantialist interpretation of some of the key notions of the Buddhist teaching and, secondly, to defend a specific view of the relation between individuals and their properties.
