NP-completeness of two pencil puzzles: Yajilin and Country Road

Ishibashi, Ayaka; Sato, Yuichi; Iwata, Shigeki

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Inviting Applications for Editorial Board Membership

August 12, 2025

Greetings from the Utilitas Mathematica (e-ISSN: 0315-3681) A Canadian journal of applied mathematics, computer science and statistics

We are pleased to announce that the Utilitas Mathematica is currently inviting qualified researchers, academics, and professionals to join our Editorial Board.

As a peer-reviewed, interdisciplinary journal committed to advancing knowledge in all areas of mathematics and computer science, UTM is seeking individuals with strong academic backgrounds, research expertise, and a passion for scholarly communication.

We are looking for:

Established researchers with a Ph.D. in a relevant field

Proven publication and peer review experience

Commitment to uphold ethical standards in scholarly publishing

Willingness to contribute to editorial decisions and journal development

Responsibilities include:

Reviewing submitted manuscripts

Assisting in maintaining the journal’s academic quality

Promoting the journal in your professional network

Advising on journal policies and special issues.

How to Apply:

Please submit your CV, list of publications, and a brief statement of interest to:

[editor@utilitasmathematica.com]

Join us in shaping the future of scientific publishing and innovation!

Sincerely,

Editorial Office

Utilitas Mathematica

Journal URL: https://utilitasmathematica.com/index.php/Index

It’s important to remain vigilant against deceptive websites:

July 18, 2025

Due to unavoidable circumstances, journal publications experienced a temporary suspension, during which misleading domains such as https://combinatorialpress.com/um/ (see in this all journals are clone) and www.combinatorialmath.com appeared. While the latter remained dormant, the former, under the guise of Utilitas Mathematica, disseminated unverified content that does not uphold the true legacy of Utilitas Mathematica.

Note: https://www.youtube.com/watch?v=iMXgA7q5pzE see

Editorial Team

Paper Selection and Publishing Process

Paper Selection and Publishing Process

a) Submission Acknowledgement

When you submit a manuscript online, you will receive a submission acknowledgment letter sent by the online system automatically. For email submission, the editor or editorial assistant sends an e-mail confirmation to the submission’s author within one to three working days. If you fail to receive this confirmation, please check your bulk email box or contact the editorial assistant.

b) Basic Review

The editor or editorial assistant determines whether the manuscript fits the journal’s focus and scope. Next, a check for the similarity rate is done using CrossCheck, powered by iThenticate. Any manuscripts out of the journal’s scope or containing plagiarism, including self-plagiarism, are rejected.

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c) Peer Review

At least two peer-reviewers will review every submitted paper. Reviewers are unaware of the authors' identity, and authors are also unaware of the identity of reviewers (double-blind review method). Reviewing process will consider novelty, objectivity, method, scientific impact, conclusion, and references. Reviewers' comments are then sent to the corresponding author for necessary actions and responses. The suggested decision will be evaluated in an editorial board meeting. Afterward, the editor will send the final decision to the corresponding author. The review process may take four to six weeks.

d) Decision is Made

The decision to accept or reject an article is based on the suggestions of reviewers. If differences of opinion occur between reviewers, the editor-in-chief will weigh all comments and arrive at a balanced decision based on all comments, or the second round of peer review may be initiated.

e) Notification of the Result of Review

The result of the review will be sent to the corresponding author and forwarded to other authors.

f) Publication Notice

The authors and readers will be notified and invited to visit our website for the newly published articles.

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NP-completeness of two pencil puzzles: Yajilin and Country Road

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