The phrase "as ultimate proof" is correct and usable in written English.
It can be used when you want to emphasize that something serves as the final or most conclusive evidence for a claim or argument.
Example: "The results of the experiment were published in a peer-reviewed journal, serving as ultimate proof of the theory's validity."
Alternatives: "as conclusive evidence" or "as definitive proof".
Mr. Warner took that Earley loss as his own victory and as ultimate proof that his "I'm a conservative too" message on the stump and on television was hitting home.
Often, crystal structure determination is regarded as ultimate proof for ligand binding providing detailed insight into the specific binding mode of the ligand to the protein.
Knockout mutants could serve as ultimate proof for ZmTSA being essential.
If he had to impose a view, he would reluctantly signify that intention by using the expression "I strongly recommend.... ........ And, as ultimate proof of true intelligence and integrity, he was fully capable of admitting when he was wrong.
Being able to manage all alone was regarded as the ultimate proof of being courageous as opposed to being a coward who required assistance.
A third competition was also under way, this one closer to home, in products to enhance the everyday life of the average citizen as the ultimate proof of a country's merits.
Their short speaking stints are a sign not only of the growing presence of offspring in the Kerry-Edwards image-making operation, but also of the newly prominent roles that politicians' children have generally as the ultimate proof of their parents' values.
In the corporate world/culture, this is still regarded as the ultimate proof of your mastery.
Reviewer 1 In the first paragraph of Discussion, you mention that you use "distinct folds (as) the ultimate proof of analogy", which is fine.
Until now, GC-C-IRMS analysis was performed whenever a urine sample showed a T/E ratio above the threshold and was considered as the ultimate proof of doping if the carbon isotopic ratio of T or its metabolites was significantly different from one of the defined endogenous reference compounds.
Worse, the Bay of Pigs re-enactment he ordered up is produced as a musical, the ultimate proof that the revolution will die when he does.
