Editor's note: We are pleased, with this poem by our Deputy Editor Richard Grant, to launch The League of Imaginary Cats, a series of stories (or poetry), each of which is coupled to the author's thoughts about the scientific inspiration behind. Read more about the Series in our accompanying editorial.

How many times can something go
into nothing?
Or – put another way – nothing
into something?

When the number that is not a number
is divided by another number
it becomes no less;
yet no more.

When zero
is added to zero
there is śūnya,

But when I met you
this Zero became
more than the universe itself.

Suck on that, Brahmagupta.

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The idea that subtracting a number from itself yields a quantity that needs an identity is not obvious. Brahmagupta was a 7th Century Indian astronomer who defined ‘zero’ (शून्य) in those very terms, and who is generally considered to be the first to treat zero as an actual number.

In his book Brahmasphuṭasiddhanta (‘Correctly Established Doctrine of Brahma’), he describes operations on zero and on negative numbers – for example: “The product of a negative and a positive is negative, of two negatives positive, and of positives positive; the product of zero and a negative, of zero and a positive, or of two zeros is zero”.

Unlike modern mathematicians, however, Brahmagupta held that dividing zero by itself equalled zero. In modern times dividing by zero results in something undefined or meaningless.

There is no record of Brahmagupta’s love life.