What is the simplest equation ?

There are a few candidates so please justify your offering.

An identity equation that stays true for any value assigned to its variables.

1 hour ago, MigL said:

An identity equation that stays true for any value assigned to its variables.

Ah but which one ?

You mentioned variables in the plural.

The one I am thinking of has essentially one variable.

Sorry it's been so long off line I've forgotten how to hide spoilers, it doesn't seem automatic.

Edited 1 hour ago1 hr by studiot

2 hours ago, studiot said:

What is the simplest equation ?

There are a few candidates so please justify your offering.

In science? I might vote for E=hν, on the basis that it is self-evidently very simple and is probably the most important relation for anyone who wants to understand anything about light and quantum theory. But then F=ma in mechanics is equally simple and fundamental to understanding.

I'm not even sure there is any one simplest, though. Perhaps the question is a bit like asking what is the best cheese in the world. 😊