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Thread: J. A. Nairn false claims about first to calculate split evs for finite decks

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    J. A. Nairn false claims about first to calculate split evs for finite decks

    J. A. Nairn Publications (orst.edu)

    Does anyone know this guy? He's claiming in his paper:

    [1909.13710] Exact Calculation of Expected Values for Splitting Pairs in Blackjack (arxiv.org)

    That he is the first person to get exact split EVs for finite deck splits which is patently false. It's bad enough he did it once but then he re-claimed it by posting it on arxiv's in 2019.

    I just ran across his blackjack article when I was looking for old posts of mine since I'm helping someone through the calcs, where he claims to be the first person to calculate EVs for splits exactly despite the fact that Cacarulo and I were 100% the first people who did it in 2002, Don published Cacarulo's values in BJA3 shortly after, and I helped Stuart Ethier work out his splits chapter in 2007 in the Doctrine of Chances. My CA was also being shared around in 2006 which is probably how he confirmed his numbers if not from Don's book. A bunch of people then duplicated Cacarulo and my work well before his paper.

    I had posted the methodology on the old BJ Math site. Don? Norm? Cacarulo? Do any of you know him and did he have a pseudonym at the time? I'm trying to get information before I contact him directly and if he doesn't retract it I'll be contacting arxiv's and his department chair.

    His description of the "zero-memory" and "recursive" method remind me a lot of T Hopper who used our numbers to confirm his split calcs. T Hopper, do you know this person?

    John, if you see this please contact me and confirm that you will retract your claim and cite sources appropriately.

    MGP
    Last edited by MGP; 05-25-2021 at 09:55 PM.

  2. #2
    Random number herder Norm's Avatar
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    Don't know him.
    "I don't think outside the box; I think of what I can do with the box." - Henri Matisse

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    Quote Originally Posted by Norm View Post
    Don't know him.
    Nor I. Sorry.

    Don
    Last edited by DSchles; 05-29-2021 at 07:59 AM.

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    Has anyone else noticed that Nairn's split EV's differ from those in BJA3?

    For example, for T,T vs. 2 Nairn gives a Sp1 EV of 0.315676, while BJA3 gives 0.310083. For Sp3 the difference is even larger: 0.0473715 vs. 0.033475.

    Similarly, ten splits against 4, 6, and T all show discrepancies, with Nairn's values always larger than those in BJA3.

    Any ideas why?

    Dog Hand

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    I searched this name Cacarulo and found his posts of 16 years ago on this forum. Is he still here? To use the term “exact calculation” for this computer programing just does not make any scientific sense, needless to say that a tiny change of rules will make a huge off from the EV.

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    Quote Originally Posted by Dog Hand View Post
    Has anyone else noticed that Nairn's split EV's differ from those in BJA3?

    For example, for T,T vs. 2 Nairn gives a Sp1 EV of 0.315676, while BJA3 gives 0.310083. For Sp3 the difference is even larger: 0.0473715 vs. 0.033475.

    Similarly, ten splits against 4, 6, and T all show discrepancies, with Nairn's values always larger than those in BJA3.

    Any ideas why?

    Dog Hand
    It's possible that reading pages 389-391 might give a clue.

    Don

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    Quote Originally Posted by aceside View Post
    To use the term “exact calculation” for this computer programing just does not make any scientific sense
    Why not?

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    Quote Originally Posted by Gronbog View Post
    Why not?
    In my opinion, the term “exact calculation” can only be reserved for calculations with infinite decks. All other situations can just use “plausible calculation.” The expected results and the methods being used must match.

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    Once again you have it exactly backwards.

    Infinite deck calculations are the inexact "plausible calculation" and are used as an approximation because they simplify things somewhat. The exception would be if you are analyzing an online/computer game which actually is infinite deck (such games do exist).

    Calculations which consider the removal of cards are the exact ones. They are more difficult and often impossible to perform by hand which is why we use software. Be aware that I'm referring to combinatorial analysis (CA) calculations and not simulations here.

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    Thanks for the pointer(s) to this thread. I first saw Nairn's paper, and had a brief email discussion with him regarding it (in response to some questions about my software), back in January 2011. Reviewing the latest arXiv version and comparing with that older version-- that was actually dated 2008-11-21, having been submitted and rejected by some journals-- it appears not much has changed.

    I would agree that this isn't, and wasn't, anything new in terms of what was *known* about the state of the art in exact CA at the time (even as early as 2008). However, it's a fair question how much was actually *published* then or now. We live in some small and relatively dark corners of the interwebs , and although there was plenty of detailed discussion of algorithms, even sharing of source code, in places like bjmath.com, blackjackinfo.com, and now here, I don't know how much of that detail has ever found its way into print, whether in journals or in books. (That past online discussion was very helpful in refining and correcting our understanding of pair splitting in particular, which is what Nairn is focusing on. We even found a lot of bugs-- I don't know if all of the same players are here, like k_c, ICountNTrack, etc., but I remember at least MGP's CA, but I would have to revisit those past discussions to see if the most recent software has addressed those problems, most of which I seem to recall dealt with implementation details of depleted shoe subsets, as opposed to inherent methodology issues.)

    As Don points out, it makes sense that Nairn's values won't always agree with those in BJA3, since the assumptions about playing strategy are different (ref. Nairn's Appendix A, and BJA3 p. 391). Indeed, that's what makes pair splitting interesting, is how difficult it is to even unambiguously *specify* playing strategy in the context of splitting, let alone *evaluate* (or maximize) corresponding expected value. For example, from Nairn's paper: "Zero-memory basic strategy is defined as the decision that maximizes expected value based only on knowledge of the dealer’s up card and the player’s initial two cards." We understand in much greater detail now just how much is missing from this description (and from BJA3's as well).

    Having said that, if we concede agreement on *specification* of the intended playing strategy (vs. trying to *optimize* strategy by maximizing EV), then Nairn's description of his approach, and his table of results, look accurate, if much less efficient than is (and again, was) the state of the art. (From his conclusion: "The exact calculations for multideck games have not been done and would require somewhat more computer time." We can do this for any number of decks in a fraction of a second.)

    Regarding the discussion here about the use of the term "exact," I would suggest a slightly different interpretation: a value is "exact" if (1) it's a rational number that (2) two independent humans-in-principle, or two different software implementations-in-practice, could both compute and agree on the result. For example, I would include infinite decks, even unlimited (possibly infinite) resplits, in the situations where we could reasonably talk about "exact" probabilities or expected values. That is, exact-ness doesn't speak to *practicality* of the model of the game, just on the non-Monte-Carlo nature of the computation.

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    Quote Originally Posted by ericfarmer View Post

    Regarding the discussion here about the use of the term "exact," I would suggest a slightly different interpretation: a value is "exact" if (1) it's a rational number that (2) two independent humans-in-principle, or two different software implementations-in-practice, could both compute and agree on the result. For example, I would include infinite decks, even unlimited (possibly infinite) resplits, in the situations where we could reasonably talk about "exact" probabilities or expected values. That is, exact-ness doesn't speak to *practicality* of the model of the game, just on the non-Monte-Carlo nature of the computation.
    I haven’t examined this paper but I still insist that the use of the term “exact calculation” for a deck of finite number of cards is just misleading. The paper calculated the EV for a deck of 52 cards, but has not calculated it for a deck with 26 cards. How come this is exact exact? Research is meant to be useful for the people here, after all.

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    Quote Originally Posted by aceside View Post
    I haven’t examined this paper but I still insist that the use of the term “exact calculation” for a deck of finite number of cards is just misleading. The paper calculated the EV for a deck of 52 cards, but has not calculated it for a deck with 26 cards. How come this is exact exact? Research is meant to be useful for the people here, after all.
    It is no problem to compute splits or any hand for any shoe composition/cards remaining. The only requisite is that enough cards remain to complete any possible drawing sequence without running out of cards.

    k_c

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    Quote Originally Posted by ericfarmer View Post
    For example, from Nairn's paper: "Zero-memory basic strategy is defined as the decision that maximizes expected value based only on knowledge of the dealer’s up card and the player’s initial two cards." We understand in much greater detail now just how much is missing from this description (and from BJA3's as well).
    Can you just specify a little more on this example? Greater understanding comes with greater responsibilities. I have received several dislikes and try to learn a little more into this.

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