For sure, no worries. I had the same questions as you when reading it. Fwiw, the paper is really kind of sloppy. I think it’s maybe a case of poor students not wanting to pay for GPT-4? Maybe they’ll clean it up and respond to some of the criticisms when it comes out of draft, but it doesn’t seem like very rigorous scholarship to me.

I’m talking about the models and how they’re written about in the literature. I don’t care how OpenAI brands their products.

From the paper itself:

For the additional 2000 SO questions, ChatGPT 3.5 Turbo API is used.

https://arxiv.org/pdf/2308.02312.pdf

ChatGPT is 3.5, 4 is just called GPT4