'practical proof' is a correct and usable phrase in written English.
You can use it to refer to evidence of an idea or concept that is demonstrable and verifiable in a practical way. For example, "The new model car is said to perform better than other cars on the market; a practical proof of its performance would be to compare the fuel efficiency of the new car to other cars."
Her poetry is a practical proof of rhyme as expressive, flexible, purposefully baited.
In one sense, this is just practical proof of a working assumption.
Even in speculations on military subjects it was his habit to neglect maps and diagrams, and to put the theorems to practical proof on the ground itself.
As Callow declares: "Orson Welles unstintingly and tirelessly gave himself to the cause of radicalism; few actors or directors... have given more practical proof of their profound belief in democracy".
Concurrent sea voyages provided practical proof that Earth is a globe, just as Galileo's use of his newly invented telescope in the early 17th century soon showed various other planets to be globes as well.
Magellan and Faleiro now proposed to sail west to give practical proof of their claim that the Spice Islands lay west of the line of demarcation that is, within the Spanish, not the Portuguese, hemisphere.
Unfortunately, the project did not result in a practical proof-of-concept implementation. .
The approach taken by Kindura was to design, build and evaluate a practical proof-of-concept based on existing cloud and grid storage technologies.
It approaches requiring (if it does not, in practical effect, require) proof sufficient to establish guilt in order to substantiate the existence of probable cause.
Finally, we examine the practical use of Proof Sketches, and observe that adversaries can often be reduced to much smaller violations in practice than our worst-case bounds suggest.
But for most people, most of the time, it is likely that practical and idiot-proof appliances will fulfil not only their needs, but maybe even the ultimate potential of computing.
