That sounds like Knuth came up with them, but the notation is much older than 1976
yeah you're right. I wrote that poorly and seems I can't edit it now..
In the link I shared, he does propose the similar theta and omega notations and provides the existing definition for big O.
I learned them as Landau notation which would put its invention around the turn of the twentieth century.
Best explanation of big-O I've read, in a single opening sentence, no less!
That doesn't define little-o at all?
In fact, he refers to Landau for the definition of little-o.