https://github.com/ollama/ollama/blob/main/docs/modelfile.md...
Edit: Looks like both work together. "Works together with top-k. A higher value (e.g., 0.95) will lead to more diverse text, while a lower value (e.g., 0.5) will generate more focused and conservative text. (Default: 0.9)"
Not quite sure how this is implemented - maybe one is preferred over the other when there are enough interesting tokens!