[Davidzheng]

Honestly for research level math, the reasoning level of Gemini 3 is much below GPT 5.2 in my experience--but most of the failure I think is accounted for by Gemini pretending to solve problems it in fact failed to solve, vs GPT 5.2 gracefully saying it failed to prove it in general.

[mapontosevenths]

Have you tried Deep Think? You only get access with the Ultra tier or better... but wow. It's MUCH smarter than GPT 5.2 even on xhigh. It's math skills are a bit scary actually. Although it does tend to think for 20-40 minutes.

[Davidzheng]

I tried Gemini 2.5 Deep Think, was not very impressed ... too much hallucinations. In comparison GPT 5.2 extended time hallucinates at like <25% of the time and if you ask another copy to proofread it goes even lower.

[mapontosevenths]

I never tried 2.5. Three is pretty solid though, at least for my use case.

If there's a specific query you want me to run through it for comparison I'm happy to give it a go.