[Numbers upon numbers pile,
Mountains millions high,
Time on time and world on world amass,
Then, if from the dreadful hight, alas!
Dizzy-brained, I turn thee to behold,
All the power of number, increased thousandfold,
Not yet may match thy part.
Subtract what I will, wholly whole thou art.]
[1959]. A collection of terms is infinite when it contains as parts other collections which have just as many terms in it as it has. If you can take away some of the terms of a collection, without diminishing the number of terms, then there is an infinite number of terms in the collection.—Russell, Bertrand.