"constituted a proof" is correct and can be used in written English.
You can use it when you want to explain that something constituted evidence for something else. For example, "The fact that she had kept the incriminating document for years constituted a proof of her guilt."
Nevertheless, this trial constituted a proof-of-principle that SVR can be achieved by all-oral regimens, especially in patients infected with HCV subtype 1b.
The tax increase, the ministry added, "constitutes a proof of the government's determination to guarantee the deficit targets for this year".
Our results do not constitute a proof of unitarity.
These reasons do not constitute a proof that there are such entities as events.
It seems clear that no version of the moral argument constitutes a "proof" of God's existence.
First results constitute a proof of concept that the platform works and enables us to test the hypotheses.
On the other hand, theists have replied that even if this objection be true it does not constitute a proof that the God of theism does not exist.
This experimental model constitutes a "proof of concept" for the use of Brucella-GFP vaccines and associated diagnostic tests to distinguish vaccinated from naturally Brucella infected animals.
This device constitutes a proof of concept in a series of low energy trials performed using glycerin and phosphoric acid as working liquids.
There is an algorithm to recover the formulas that constitute a proof of the type of the combinator, moreover, the algorithm produces a proof that is minimal and well-structured.
Between the extremes we find the view that, even if no picture alone is a proof, visual representations can have a non-superfluous role in reasoning that constitutes a proof.
