For the experiment to be valid, it is essential to record the data accurately.
Their arguments were valid a hundred years ago and they still hold good today.
You need to trawl through a lot of data to get results that are valid.
The voucher is valid between July and December and entitles you to 10% off all overseas flights.
The analysis we present is not restricted to electron-ion plasmas, the result is also valid for electron-positron plasmas.
A coupling of this premise with the original premise will yield the conclusion by simple application of modus ponens, thus making the revised argument valid.
Both representations are valid and may be used in different contexts.
