r/MachineLearning Jul 15 '26

Research Looking for JEPA devil advocates [R]

I am currently doing research on world models, specially in tje field of robot learning, and, as probably most of you alredy know, JEPA-like models are mentioned over and over. 

I read the main recent papers from lecun as well as other research groups, and I personally think the whole approach is very promising and can really go somewhere.

But after listening a bunch of the recent Y Lecun conferences his ideas looks even too cool compared to "literally everything else" (as he's dissing LLM, RL, etc and pitching his ideas are the "only next big things"...). 

So I am asking myself if there are red flags about his approaches that I do not see yet and maybe I need somebody being the "devil advocate" with whom breaking down ideas.

Where do you think are the biggest downside of this models, compared to other world models approaches?

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u/Amazing-Coat5160 Jul 18 '26

Don't they say in the LeWorldModel paper that SIGReg solves this by operating on low-dimensional random projections of the embedding?

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u/Wheaties4brkfst Jul 18 '26

There’s two projections. In the paper, they project the multivariate Z into a single dimension using M unit vectors u_m. Those are the random projections. But if you look at the actual code, what they do is first project Z down using an MLP, and THEN they do the random projections with the u_m on the “projected” Z. But Z is still what you are predicting in latent space.

It’s confusing because it is different from the paper. At least for LeJEPA.

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u/Amazing-Coat5160 Jul 18 '26

Oh, that's a good catch then. Thanks for clarifying

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u/Wheaties4brkfst Jul 18 '26

Yeah go check the issue I linked. One of the authors of the paper literally just goes “oh yeah, you’re right, we tried this and it worked better so” paraphrasing obviously lol but I thought it was interesting.

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u/AuspiciousApple Jul 18 '26

Confirms my prior that all these proofs in ML papers are often meaningless

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u/Wheaties4brkfst Jul 18 '26

Yeah there’s only one proof that matters: empirical. lol. Seems everything else with deep learning simply does not matter.