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by jj12345 3056 days ago
Thanks for the paper link! I've been digging into PAC learning so I'm taking anything I can get.

On the paper, I was hoping you could help me understand a few things: - It seems that the main finding is that any k-CNF form, like Thomas' Boolean Regulatory Network, can be expressed by PAC learning bounds. In section 4 of the abstract [1], you mentioned that "when the dimension increases... the PAC learning algorithm can leverage available prior knowledge...". Are you referring to the time dimension adding more clauses to the k-CNF? - I'm having trouble reconciling the PAC term "h" with "model confidence" in section 5.2. Is this allowed because the PAC learning "delta" (probability) [2] parameter is dropped for the k-CNF adaptation? - In this concrete case, is the learning portion just the mapping the stochastic traces to outputs (i.e. lookups)? I'm missing some understanding on how such a mapping handles stochasticity.

You'll have to forgive me, as I'm still trying to understand the paper. It's incredibly interesting to me, so thanks for writing it!

[1] Abstract - http://mlsb.cc/2017/abstracts/MLSB_2017_paper_11.pdf

[2] PAC Learning - https://en.wikipedia.org/wiki/Probably_approximately_correct...

1 comments

Hi ! I'll try to answer your questions as I can :

Unfortunately the final version of the paper is not the one that is on hal -- which is an older one, and I must concede that being new to this whole publishing world, I don't know exactly how you can have access to it. I'll try to sort it out and get back to you. In the mean time, you can refer to the hal version.

  In section 4 of the abstract [1], you mentioned that "when the dimension increases... the PAC learning algorithm can leverage available prior knowledge...". Are you referring to the time dimension adding more clauses to the k-CNF?
I think this sentence is actually referring to what is presented in section 5.3 of the final (and hal version) paper.

  I'm having trouble reconciling the PAC term "h" with "model confidence" in section 5.2. Is this allowed because the PAC learning "delta" (probability) [2] parameter is dropped for the k-CNF adaptation?
I think there are two things here.

First the "delta" you are referring to is indeed taken to be equal to the "epsilon" and both are what we call "h" in section 2.1.

Second, the idea of the discussion in section 5.2 is the following: let's say you fix a number A of initial states and simulate B steps of for each of these states. You will have a given number of (de)activation samples for each (de)activation function. Then, accross all 2n (de)activation functions, take the minimum number of samples you got, and call it Lmin. Then using results from section 2.2, with S=(2n)^(k+1), you can find h so that Lmin=2h(S+log(h)). This h will be your "model confidence".

However, if we didn't have one "h" but one "delta" and one "epsilon" (wikipedia notations), I guess we would not have a given value but only a relation between the two (i.e. defining one would define the other).

I'm afraid I don't get your last point.

I'm new to HN so I hope this answer will be somewhat correctly formatted.

Thanks, these are great responses! Also, I apologize for not fixing my own formatting sooner, which makes the questions almost impossible to read. You answered my last question about stochastic traces by explaining the de/activation function relationships with Lmin.

Thanks again!