The phrase "a proposition which" is correct and usable in written English.
It can be used when introducing a statement or idea that is being defined or explained further.
Example: "The researcher presented a proposition which challenged the existing theories in the field."
Alternatives: "a statement that" or "an assertion which".
This is a proposition which very few major European allies buy.
San Francisco rejected a proposition which would have imposed restrictions on home-sharing platforms such as Airbnb after a summer of political campaign.
We are a creedal nation, dedicated to a proposition, which is approximately this: All people are created equal and have a right to spacious freedom that produces unequal outcomes.
Lambert of Lagny describes the many aspects of a proposition which can produce ampliation or restriction.
We begin with a proposition which is needed to prove the main theorem of this section.
Now we give a proposition, which will be applied to prove Theorem 1.1.
According to Kant, belief in God is "a postulate of pure practical reason": "a theoretical proposition which is not as such demonstrable, but which is an inseparable corollary of an a priori unconditionally valid practical law" (CPrR 5 122).
A singular proposition is to be contrasted with a general proposition, which is not about any particular individual, and a particularized proposition, which is about a particular individual but does not contain that individual as a constituent.
A structured proposition which, like the preceding one, has an individual as a constituent, is a singular proposition.
Just as surely, though, these new engagements will expose people in the world's most reclusive nation to outside influences, a risky proposition, which perhaps explains why such an opening has not been tried before.
Even at its most raging, Toro y Moi's music is an insular proposition, which in a room the size of this one, has its limitations.
