Wikipedia

Talk:Markov chain#Semi-protected edit request on 13 June 2024

Semi-protected edit request on 13 June 2024

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HI,the page was bloked, however, some users abused the system and erased Gagniucs book with no reason. I wish to insert Gagniucs book again, and the main reason is the fact that is the most academically cited book listed on this page. More ... the suspicious reason for wich a top book was erased on no grounds at all except replacement with other unknown sources that have no academic grounds to be cited. 213.233.108.161 (talk) 20:40, 13 June 2024 (UTC)[reply]

Declined. There was no "abuse" of "the system". Gagniuc's book was removed for multiple reasons, any one of which would have been sufficient by itself. "Most academically cited book listed on this page" is a meaningless standard, particularly since the book could well have benefited from having been advertised here for so long. XOR'easter (talk) 20:51, 13 June 2024 (UTC)[reply]
To anyone reading this:
  • The account @Dudumanad was created fairly recently (March 2025), and their very first edit on the main space was fixing the formatting around the citation of Gagniuc's book
  • Pretty much all of their edits after this have been mass-adding citations of another book by Gagniuc: [1], [2], [3], [4], [5]
  • You always have the option of going take a look at Gagniuc's book for yourself.
  • "It’s also worth remembering that in 2017, when this book was published, Markov chains were not nearly as widely discussed outside of core probability theory or niche applications." → Yeah. Right.
Malparti (talk) 12:56, 22 June 2025 (UTC)[reply]
The idea that Markov chains were a niche topic in 2017 is laughable. The vacuity of the prose and its failure to engage with any of the substantive criticisms make me wonder if it's partly or largely AI slop. Stepwise Continuous Dysfunction (talk) 19:22, 22 June 2025 (UTC)[reply]

Proposal to reintroduce peer-reviewed source (Wiley, 2017)

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Hello everyone,

I would like to propose reintroducing a citation to a peer-reviewed academic book published by Wiley in 2017:

📘 Markov Chains: From Theory to Implementation and Experimentation by P.A. Gagniuc.

ISBN: 978-1-119-38755-8

The book provides a clear, structured overview of both the formal definitions and the historical development of Markov chains, including references to the work of Andrey Markov himself.

The source is:

  • Peer-reviewed and published by Wiley (a major academic publisher)
  • Cited over 1,000 times in the academic literature
  • Directly relevant to the introductory definitions in this article

I understand concerns about citations in the lead, but in this case, the source is used to support factual information about definitions and history, not any personal opinion or promotional claim.

Suggested reinsertion:

The theory of Markov chains, which are mathematical systems that transition from one state to another within a finite or countable number of possible states, has its foundations in the early 20th century through the work of Andrey Markov. A comprehensive overview of both the historical context and formal definitions is provided by Gagniuc (2017), in a peer-reviewed academic volume published by Wiley.<ref>Gagniuc, P.A. (2017). Markov Chains: From Theory to Implementation and Experimentation. Wiley. ISBN 978-1-119-38755-8.</ref>

Please let me know if there are any policy-based objections to this. Otherwise, I plan to reinsert it into the article in 48 hours. EricoLivingstone (talk) 12:16, 31 March 2025 (UTC)[reply]

Hi @EricoLivingstone.
Please see the following discussion: Advice on dealing with questionable citations in lead. I also encourage you to have a look at the book itself.
I'll summarize the main points here. First, concerning the book itself:
  • it is full of inaccuracies (and even blatant mistakes) on the basics;
  • It is far from being a comprehensive overview of the subject: it covers only a small subset of what most textbooks on Markov chains cover;
  • This last point is subjective, but all of the other editors who have had a look at the book seemed to agree with me: the book is "outstandingly poorly" written (please have a look at the 100+ pages of printed computer code and tell me how this can useful to anyone).
Since there is no shortage of excellent textbooks of Markov chains, there is no good justification to cite Gagniuc's book rather than one of the classics. Also, the fact that it was published by Wiley doesn't give it any right to be cited on Wikipedia: it merely makes it eligible for that. Not every published book / scientific article has to be on Wikipedia.
Second, there has been some shady business going on around Gagniuc's book. In particular, its introduction on Wikipedia seems to have resulted from a concerted spamming effort by both registered editors (e.g, the now-banned User:MegGutman) and various IP users (mostly from Romania). It is likely that this has contributed to the 1000+ citations that you mention. As a fun exercise, you can have a look at the articles that cite Gagniuc, and how they cite it.
I agree that I should have linked to the original discussion in my comment (even though, as the admin who closed your request pointed out, it wasn't too hard to find). I apologize for not doing it.
Best, Malparti (talk) 15:02, 31 March 2025 (UTC)[reply]
Thank you, Malparti. I respectfully disagree with several of your points, and I’d like to respond with policy-based reasoning:
  1. WP:RS and WP:SCHOLARSHIP – The book is peer-reviewed, published by Wiley (a recognized academic publisher), and cited in over 1,000 scholarly works. That meets Wikipedia’s standards for a reliable academic source.
  2. WP:NPOV – Your concerns about “poor writing” or “mistakes” are subjective and not sufficient for exclusion. Content inclusion is not based on personal taste but on verifiability and reliability. Please cite specific factual errors with page numbers if that’s your concern.
  3. WP:OR – Suggesting that the book gained citations through “shady business” or “spamming” is speculative and outside the scope of content policy. Unless there’s a formal ruling by admins or the RS noticeboard, such claims are considered original research or conspiracy.
  4. Relevance – The book provides a historical and definitional overview, which justifies its use in the lead or relevant sections. It’s not the only source, nor is it replacing the classics. Including multiple perspectives is encouraged under WP:DUE.
I appreciate you clarifying your views, but unless specific factual inaccuracies are documented with references, I will proceed to reinsert the citation as proposed. EricoLivingstone (talk) 15:38, 31 March 2025 (UTC)[reply]
I agree with Malparti. The consensus of multiple editors in the linked discussion on Wikipedia talk:WikiProject Mathematics/Archive/2024/Jun#Advice on dealing with questionable citations in lead is that this is a low-quality source for this topic that does not stand up to scrutiny. We have better. There is no policy that states that we must use a source merely because it has been published; we invariably have a choice for which source to use, and should make that choice based on our judgement of the quality of the source. Your insistance on spamming this source does not appear to be grounded in any encyclopedic purpose and raises suspicion that you are related somehow to the blocked editors previously blocked for promotional edits of the same material. —David Eppstein (talk) 17:37, 31 March 2025 (UTC)[reply]
Thank you for your note, David. However, I respectfully disagree with your characterization.
  • There is no formal consensus against this source — only informal agreement among a small group of editors who also happen to be actively opposing the citation across multiple pages.
  • Wikipedia policy (WP:RS and WP:SCHOLARSHIP) does not require a source to be the “best” or to win a subjective popularity contest. If it is published by a reputable academic press and cited widely, it qualifies as reliable.
  • Suspicion of connections to other editors is speculative and violates WP:AGF (Assume Good Faith). I’d prefer to keep this discussion focused on content policy and verifiability, rather than speculative assumptions about editor identity.
Unless a clear policy-based reason is presented — with page-specific counter-arguments — I will proceed with the reinsertion, in accordance with WP:V and WP:DUE. EricoLivingstone (talk) 18:08, 31 March 2025 (UTC)[reply]
Google Scholar search for "Markov chain" finds some 2 million hits, most presumably reliably published. Are you trying to suggest that policy requires us to list them all as 2 million footnotes in this article? If not, what makes you think this one source has any justification for special treatment, different from the 1999999 others?
As for suspicion of connections: You could explicitly state that you have neither a commercial nor personal connection to Gagniuc nor to User:MegGutman, rather than merely deflecting the issue. —David Eppstein (talk) 18:18, 31 March 2025 (UTC)[reply]
Thank you, David.
I never claimed that a source’s inclusion should be based solely on citation count — only that the combination of publisher reliability (Wiley) and academic citation (1,000+) meets the threshold under WP:RS and WP:SCHOLARSHIP.
Regarding your second point: I'm not suggesting we list all sources found via Google Scholar. But when a source is peer-reviewed, relevant, and cited in academic literature, its inclusion should be discussed on those merits, not dismissed by analogy.
As for the request to "explicitly state" my personal affiliations — I respectfully decline. Wikipedia policies do not require editors to disclose personal or professional identities. Disputes should be resolved through content policy, not speculation.
Let’s focus on verifiability, reliability, and relevance as outlined in WP:V, WP:RS, and WP:NPOV. EricoLivingstone (talk) 18:29, 31 March 2025 (UTC)[reply]
Please note that I have not asked you to disclose your identity. I have asked you to disclose your conflicts of interest, if you have them, as is required by Wikipedia's terms of use. THe fact that you keep refusing to respond constructively to such a request is not reassuring. —David Eppstein (talk) 20:35, 31 March 2025 (UTC)[reply]
I invite you to continue adding the material against the clear consensus of all competent editors who have considered the question, but only because that is the most direct route to your being blocked for disruptive editing. --JBL (talk) 17:57, 31 March 2025 (UTC)[reply]
Also note forum-shopping at WP:AN#Improper removal of Wiley academic source from "Markov chain" article — possible coordinated abuse and WP:DRN#Markov chain. —David Eppstein (talk) 18:06, 31 March 2025 (UTC)[reply]
Thank you, JBL. I’m aware of Wikipedia's conduct guidelines, and I’m committed to editing in accordance with WP:V, WP:RS, WP:NPOV, and WP:DUE.
I note that your comment does not address the actual content of the source or cite any policy-based reason for exclusion. Warnings about “being blocked” are not a substitute for verifiability or discussion based on Wikipedia’s content standards.
If you believe my editing is disruptive, the appropriate venue is WP:ANI. Otherwise, let’s please keep this focused on policy, not intimidation. EricoLivingstone (talk) 18:24, 31 March 2025 (UTC)[reply]
  • Just to note that this has been brought up on RSN. I suggest the discussion continue here rather than splitting it. -- LCU ActivelyDisinterested «@» °∆t° 18:26, 31 March 2025 (UTC)[reply]
    Thank you, @ActivelyDisinterested. I appreciate your note.
    I agree that centralizing discussion is helpful. I raised the issue on RSN and DRN only after Talk page attempts failed and the source was repeatedly removed with non-policy-based reasoning.
    I’m happy to follow consensus-building wherever volunteers believe is most appropriate, as long as it remains focused on policy (e.g., WP:RS, WP:SCHOLARSHIP, WP:DUE).
    I appreciate your input and willingness to help guide the process. EricoLivingstone (talk) 18:51, 31 March 2025 (UTC)[reply]
    It would be better to follow consensus-building, period. You are not the arbiter of whether other people's thoughts are valid or not - it is not up to you to judge what is acceptable reasoning and what isn't. You should be looking for compromise - for example, by finding some other citation that can support whatever the text you want to add might be. MrOllie (talk) 19:02, 31 March 2025 (UTC)[reply]
    Thank you, MrOllie. I appreciate your input.
    I’d like to clarify that I’m not acting as an “arbiter” of anyone’s reasoning — I’m simply requesting that content decisions be based on Wikipedia’s established standards (WP:RS, WP:SCHOLARSHIP, WP:V), not on subjective impressions or editor preferences.
    The Wiley source (Gagniuc, 2017) is peer-reviewed, published by a respected academic publisher, and cited in over 1,000 scholarly works. This meets all criteria for inclusion as a reliable source.
    I welcome compromise when multiple valid sources exist, but replacing a compliant source with subjective dismissals is not aligned with WP:DUE or WP:NPOV.
    If there are policy-based objections with specific examples (e.g., factual errors or RS policy violation), I’m open to discussing them. Otherwise, I believe the source deserves inclusion. EricoLivingstone (talk) 19:12, 31 March 2025 (UTC)[reply]
    Reliability doesn't guarantee inclusion. Whether to include content is an WP:NPOV matter, any included content must be verifiable to a reliable source. As long as content has a source there is no need to include more sources, Wikipedia isn't a list of all sources for a subject. The citation you added was redundant, so there is no policy based reason to reintroduce it - regardless of whether or not it is reliable. I'll leave the reliability of mathematical works to WikiProject Mathematics, who appear to have already discussed it. -- LCU ActivelyDisinterested «@» °∆t° 20:04, 31 March 2025 (UTC)[reply]
  • Noting that the instigator of this thread has been blocked indefinitely. --JBL (talk) 21:31, 31 March 2025 (UTC)[reply]

A decent source

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  • Vogt, W. Paul (2005). "Markov Chain". Dictionary of Statistics & Methodology: A Nontechnical Guide for the Social Sciences. SAGE. p. 186. ISBN 9780761988557.

A good rule of thumb for citations of introductory definitions is a good glossary or a "Dictionary of X" book. They are usually pitched at the right level, as this one would seem to be from its title. ☺ It pretty much entirely supports the first two sentences. This would leave no excuse at all for that other source to keep cropping up. Vogt taught statistics and was a professor at Illinois State University, according to xyr 2016 obituary. Uncle G (talk) 22:02, 31 March 2025 (UTC)[reply]

Rename article to "Markov process" or create separate article

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Hello everyone,

I would suggest renaming this article into "Markov process" instead of "Markov chain", since it appear to treat more than just Markov chains and "Markov process" is the more general term. Especially the case of continuous time with general state space does not really fit into the framework of Markov chains (nobody would call the Brownian Motion a Markov chain). One could change the introductory sentence to "In probability theory and statistics, a Markov process or, if time or the state space is discrete, a Markov chain is a ..." (or something similar) to still give Markov chains a prominent role in the article.

Alternatively, if the community prefers having an own article about Markov chains, I would propose creating a separate article about Markov processes, where continuous-time Markov processes can be discussed, and refer to the main article about Markov chains for this special case. Simon Bienewald (talk) 07:47, 2 November 2025 (UTC)[reply]

Hi @Simonbiene,
I agree with you, and I sympathize. However, I anticipate that this could prove a bit tricky to implement, because of disagreements on how articles should be named and on what should go in which articles... For instance, note that the current version of this article is largely the result of the merge between an article that was called "Markov chain" and another one called "Continuous time Markov chain". The restructuring should also take into account the existence of articles such as Markov model and Markov property.
One solution which I think would be somewhat OK — or at least better than what we currently have — would be the following:
  • Markov process (to which Markov chain and possibly Markov model would redirect) — a non-technical introduction to Markov processes that presents the general idea behind the Markov property, explains that in some contexts the word "chain" is used, and quickly redirects the reader other articles listed below (as well as some of the articles currently listed in Markov model — I don't know much about this topic — and articles such as Diffusion process, etc)
  • Discrete-time Markov chain — a somewhat technical but very accessible on discrete-time Markov chains (on a discrete state-space).
  • Continuous-time Markov chain — a somewhat technical but very accessible on continuous-time Markov chains (on a discrete state-space).
  • Markov property — a technical article about general Markov processes. This would also redirect to most of the article listed in Markov process.
However, this solution isn't perfect either. For instance, it would probably lead many people to link to the technical article Markov property instead of the non-technical article Markov process...
In the end, I think the problem comes from the following facts:
  1. We need technical and non-technical articles on topics such as Markov processes/the Markov property, and both can legitimately claim the same name (of course, ideally this problem would be solved by having articles that are non-technical in the beginning and get progressively more technical; but that would result in huge articles that would be: hard to uniformize and maintain; intimidating to readers who want the non-technical part; unnecessarily hard to navigate for readers who want the technical part — which is why would personally favor splitting such articles).
  2. This topic is of interest to many people with very different backgrounds (probabilists, statisticians, data scientists, physicists, etc) who all see it as their topic.
At any rate: I'm happy to take part in the discussions to see if a consensus can be reached on how to restructure things. And if that can be done, I am also happy to help implement the changes. Malparti (talk) 14:39, 2 November 2025 (UTC)[reply]
Hi @Malparti,
thank you very much for your input and your willingness to improve the article(s).
I didn't know about the former merge of the articles about Markov processes and CTMC (because the article still exists), which suggests that it shouldn't be splitted again, I guess. I somehow like your idea of discussing general Markov processes in the Markov property article, since they are canonically linked via "Markov processes are processes with the Markov property". However, I would like to include (technical) topics such as h-transforms and time reversal somewhere (because they are used in the field of diffusion models today, see e.g. First Hitting Diffusion Models), which do not directly have something to do with the Markov property itself, but rather with the transition probabilities (=transition semigroup) of a Markov process.
So maybe it makes sense to transform the Markov property article into a "Markov process" article in the way you proposed, but with different definitions of the Markov property at different technical levels and with topics related to continuous-time Markov processes such as the ones above.
Concerning the levels of technicality: The issue I see with having technical and non-technical articles, is that every topic has technical and non-technical aspects, which would need to always build at least two articles (which I don't think would be easy to maintain either). Instead, a single article starting at an accessible level and having designated technical sections should resolve some of your concerns (intimidating non-technical readers and lost technical readers). Simon Bienewald (talk) 15:55, 2 November 2025 (UTC)[reply]
If it is possible to combine the non-technical introduction and the technical stuff in a single article, that would be ideal; it just seemed like more work. Also, my impression after having the "Markov chain" on my watch list for a few years now is that it is a monstrosity that keeps growing in all directions (mostly concerning applications and examples) and has to be trimmed on a regular basis so it doesn't become... Absurd. But that's probably just lazy me speaking! :) Malparti (talk) 22:43, 2 November 2025 (UTC)[reply]

Applications takes a quarter of prose size?

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The Applications section of the article is quite long and takes up close to 2,000 words in prose size (I used wordcounter.net on copied text so it's not exact). Compared to the almost 7,000 words of prose, it's over a quarter of the article's length.

It seems to me that since Markov chains are widely used across disciplines, anyone with enough familiarity of their field could potentially add another section. I think it would be better if we moved most of the information to a separate article, "Applications of Markov chains", and kept a small paragraph to highlight a few short applications while linking to the main article. It might also make sense to fold some of the Examples of Markov chains article into the potential new "Applications" article.

What do you all think?

Moon motif (talk) 05:58, 6 December 2025 (UTC)[reply]

I should've looked in the talk page archives before adding this topic. It seems that there was a similar discussion five years ago [6]. Pinging the people in discussion in case they want to chime in: @Malparti @Gaba_p @QueensanditsCrazy
Moon motif (talk) 06:10, 6 December 2025 (UTC)[reply]
This article's length: roughly 6900 words "readable prose size" (not counting references, tables, etc). This puts it below the lowest size at which WP:TOOBIG suggests splitting. That is, we currently do not have a size problem. If we do, we can revisit this. And your comment itself suggests that the applications of Markov chains are an important subtopic, important enough that they be represented with a significant fraction of the total article content. —David Eppstein (talk) 06:28, 6 December 2025 (UTC)[reply]
@David Eppstein I agree that the article itself isn't too long. I also agree that applications of Markov chains are an important topic. However, I think we do have a problem with this section — in particular regarding its importance relative to the article (this is probably better reflected by the table of contents and number of references than by the word counts); its structure (why is "Solar irradiance variability" at the same level as "Physics"?); and concerns of citespam.
I think a good parallel can be made between Markov chains and ordinary differential equations:
  • the development of both was in great part motivated by applications;
  • both topics are pretty well understood, so that in the basic setting there isn't a ton of research on the theory itself (people prefer to work on the theory of e.g. PDEs or Markov processes on exotic state spaces)
  • thus, they have become a basic tool that is routinely used in pretty much every field of science.
Yet if we look at Ordinary differential equation, it does not have such a huge and poorly-structured section on applications. Differential equation has one, but it is quite short and remains generic, instead of citing specitic articles.
I'll try to get some stats on the references to see if they support my point. Malparti (talk) 12:04, 6 December 2025 (UTC)[reply]
Here are some data:
  • The section "Applications" has 50 references — out of the 112 references of the article (note that some references are duplicated, such as 72 and 73).
  • Of these, 14 are textbooks / lectures notes / websites, and 36 are research articles. A few of these are old classics (e.g., Bachelier's article, published in 1900); but most are fairly recent (19 were published in the last 20 years).
  • Most of these articles are highly cited (median number of citations: 147 — and the average is 1868), but 11 of them are cited less than 50 times.
After looking at this, I will:
  • Trim the first paragraph of the section — the choices of examples used here is arbitrary.
  • Remove the subsection "Testing" — it does not make a lot of sense to me and has no supporting citations anyway.
  • Remove the subsection "Conflict and combat" — the number of citations of the references suggest that this is not a notable application; at least, not at the same level as "Physics".
  • Remove the subsection "Solar irradiance variability" — this is a legitimate application, but it is also very specialized and in my opinion it does not make sense to have it at the same level as entire disciplines, such as "Physics", "Chemistry" or "Biology".
That's a start, but in my opinion there will still be a lot of work to do. Malparti (talk) 13:41, 6 December 2025 (UTC)[reply]
I didn't realize we had size guidelines, good to know. In that case, I agree that it'd be best not to split for now. The idea to split mainly came from seeing the Examples of Markov chains article and thinking that applications were at least as interesting/important as its examples (though now I wonder why examples has its own article...) Moon motif (talk) 17:05, 6 December 2025 (UTC)[reply]
I actually think the section is fine as is. Length is reasonable. As long as none of the examples listed are too niche or anything. QueensanditsCrazy (talk) 15:53, 6 December 2025 (UTC)[reply]
@QueensanditsCrazy when you say "as it is", do you mean this or this? The article is 6800-bytes / 4-subsections shorter than when this discussion was started. Malparti (talk) 16:14, 6 December 2025 (UTC)[reply]
They're both fine to me tbh QueensanditsCrazy (talk) 13:09, 8 December 2025 (UTC)[reply]
@QueensanditsCrazy OK.
Since 3 of the 4 sections that I've just removed were among the section that thought were "unnoteworthy and worthy of deletion" ~5.5 years ago (the fourth one had been added to the article ~1 year ago), it looks like past-you and present-I independently came to the conclusion that the article would be better off without those sections. Given that @Moon motif seems to agree with that and that neither present-you nor @David Eppstein seems to actively disagree (?), I take it that for now the consensus is in favor of removing those sections. Or course that may change if someone pops in to say they disagree.
Cheers, Malparti (talk) 16:10, 8 December 2025 (UTC)[reply]