A. Journal Papers

• A. C. Cem Say, Selahattin Kuru, "Improved filtering for the QSIM algorithm," IEEE Transactions on Pattern Analysis and Machine Intelligence Vol. 15, pp. 967-971, 1993.

• A. C. Cem Say, Selahattin Kuru, "Qualitative system identification: Deriving structure from behavior," Artificial Intelligence Vol. 83, pp. 75-141, 1996.

• A. C. Cem Say, Selahattin Kuru, "Postdiction using reverse qualitative simulation," IEEE Transactions on Systems. Man, and Cybernetics Part A: Systems and Humans Vol. 27, pp. 84-95, 1997.

• A. C. Cem Say, "L'Hôpital's filter for QSIM," IEEE Transactions on Pattern Analysis and Machine Intelligence Vol. 20, pp. 1-8, 1998.

• A. C. Cem Say, "Making use of contradictory behavior information in qualitative reasoning," IEEE Transactions on Pattern Analysis and Machine Intelligence Vol. 21, pp. 781-786, 1999.

• A. C. Cem Say, "Understanding arithmetic problems in Turkish," International Journal of Pattern Recognition and Artificial Intelligence Vol. 15, pp. 359-374, 2001.

• A. C. Cem Say, "Improved reasoning about infinity using qualitative simulation," Computing and Informatics Vol. 20, pp. 487-507, 2001.

• A. C. Cem Say, "Problems in representing liquid tanks with monotonicity constraints: A case study in model-imposed limitations on the coverage of qualitative simulators," Artificial Intelligence Review Vol. 17, pp. 291-317, 2002.

• A. C. Cem Say, "Sound and complete qualitative simulation requires "quantitative" filtering," Annals of Mathematics and Artificial Intelligence Vol. 38, pp. 257-267, 2003.

• Tolga Könik, A. C. Cem Say, "Duration consistency filtering for qualitative simulation," Annals of Mathematics and Artificial Intelligence Vol. 38, pp. 269-309, 2003.

• A. C. Cem Say, H. Levent Akın, "Sound and complete qualitative simulation is impossible," Artificial Intelligence Vol. 149, pp. 251-266, 2003.

• A. C. Cem Say, A. Kutsi Nircan, "Random generation of monotonic functions for Monte Carlo solution of qualitative differential equations," Automatica Vol. 41, pp. 739-754, 2005.

• Özgür Yılmaz, A. C. Cem Say, "Causes of ineradicable spurious predictions in qualitative simulation," Journal of Artificial Intelligence Research, Vol. 27, pp. 551-575, 2006.

• Abuzer Yakaryılmaz, A. C. Cem Say, "Efficient probability amplification in two-way quantum finite automata," Theoretical Computer Science, Vol. 410, pp. 1932-1941, 2009. (doi:10.1016/j.tcs.2009.01.029)

• Rūsiņš Freivalds, Abuzer Yakaryılmaz, A. C. Cem Say, "A new family of nonstochastic languages," Information Processing Letters, Vol. 110, pp. 410-413, 2010. doi: 10.1016/j.ipl.2010.03.011

• Abuzer Yakaryılmaz, A. C. Cem Say, "Languages recognized by nondeterministic quantum finite automata," Quantum Information and Computation, Vol. 10, pp. 747-770, 2010.

• Abuzer Yakaryılmaz, A. C. Cem Say, "Succinctness of two-way probabilistic and quantum finite automata," Discrete Mathematics and Theoretical Computer Science, 12(4), pp.19-40, 2010.

• Abuzer Yakaryılmaz, A. C. Cem Say, "Unbounded-error quantum computation with small space bounds," Information and Computation, Vol. 209, pp.873-892, 2011. [slightly older version at arXiv:1007.3624]

• Abuzer Yakaryılmaz, Rūsiņš Freivalds, A. C. Cem Say, Ruben Agadzanyan, "Quantum computation with write-only memory," Natural Computing, Vol. 11, pp.81-94, 2012. doi: 10.1007/s11047-011-9270-0

• A. C. Cem Say, Abuzer Yakaryılmaz, "Computation with multiple CTCs of fixed length and width," Natural Computing, Vol. 11, No. 4, pp. 579-594, 2012. doi: 10.1007/s11047-012-9337-6 (errata)

• A. C. Cem Say, Abuzer Yakaryılmaz, "Quantum counter automata," International Journal of Foundations of Computer Science, Vol. 23, No. 5, pp. 1099-1116, 2012. doi: 10.1142/S012905411250013X

• Abuzer Yakaryılmaz, A. C. Cem Say, "Proving the power of postselection," Fundamenta Informaticae, Vol. 123, No. 1, pp. 107-134, 2013.

• Abuzer Yakaryılmaz, A. C. Cem Say, "Tight bounds for the space complexity of nonregular language recognition by real-time machines," International Journal of Foundations of Computer Science, Vol. 24, No. 8, pp. 1243-1253, 2013. DOI.

• A. C. Cem Say, Abuzer Yakaryılmaz, "Finite state verifiers with constant randomness," Logical Methods in Computer Science, Vol. 10(3:6)2014, pp. 1-17. (errata)

• Uğur Küçük, A. C. Cem Say, Abuzer Yakaryılmaz, "Finite automata with advice tapes," International Journal of Foundations of Computer Science, Vol. 25, No. 8, pp. 987-1000, 2014.

• H. Gökalp Demirci, A. C. Cem Say, Abuzer Yakaryılmaz, "The complexity of debate checking," Theory of Computing Systems, Vol. 57, pp. 36-80. DOI 10.1007/s00224-014-9547-7, 2015. http://eccc.hpi-web.de/report/2014/016

• Abuzer Yakaryılmaz, A. C. Cem Say, H. Gökalp Demirci, "Debates with small transparent quantum verifiers," International Journal of Foundations of Computer Science, Vol. 27, No. 2, pp. 283-300, 2016. arXiv: 1405.1655

• Özlem Salehi, A. C. Cem Say, Flavio D’Alessandro, "Homing vector automata," RAIRO-Theor. Inf. Appl., Vol. 50, pp. 371–386, 2016.

• A. C. Cem Say, Abuzer Yakaryılmaz, “Magic coins are useful for small-space quantum machines", Quantum Information & Computation 17.11&12 (2017), pp. 1027-1043.

• Uğur Küçük, A. C. Cem Say, Abuzer Yakaryılmaz. “Inkdots as advice for finite automata”, Discrete Mathematics and Theoretical Computer Science Vol. 19:3, 2017, #1.

• Ryan O’Donnell, A. C. Cem Say, "The weakness of CTC qubits and the power of approximate counting," ACM Transactions on Computation Theory Vol. 10:2, #5, 2018.

• Özlem Salehi, Flavio D’Alessandro, A. C. Cem Say, “Language classes associated with automata over matrix groups” RAIRO-Theor. Inf. Appl., Vol. 52, pp. 253–268, 2018.

• Gökalp Demirci, Mika Hirvensalo, Klaus Reinhardt, A. C. Cem Say, Abuzer Yakaryılmaz, “Alternating, private alternating, and quantum alternating realtime automata,” Logical Methods in Computer Science, Volume 15, Issue 3, 2019, pp. 22:1–22:21

• Özlem Salehi, Abuzer Yakaryılmaz, A. C. Cem Say, "New results on vector and homing vector automata," International Journal of Foundations of Computer Science, Vol. 30, No. 8, pp. 1335-1361, 2019.

• M. U. Gezer and A. C. C. Say, “Constant-space, constant-randomness verifiers with arbitrarily small error,” Information and Computation, Volume 288, October 2022, 104744 https://doi.org/10.1016/j.ic.2021.104744

• Ahmet Bilal Uçan, A. C. Cem Say, “Advice hierarchies among finite automata,” Information and Computation, Volume 288, October 2022, 104878 https://doi.org/10.1016/j.ic.2022.104878

• M. Utkan Gezer, Özdeniz Dolu, Nevzat Ersoy, A. C. Cem Say, “Real-time, constant-space, constant-randomness verifiers,” Theoretical Computer Science, Vol. 976, October 2023, 114155 https://doi.org/10.1016/j.tcs.2023.114155

• Fırat Kıyak, A. C. Cem Say, “Energy complexity of regular languages,” Theoretical Computer Science, Vol. 982, January 2024,  114291 https://doi.org/10.1016/j.tcs.2023.114291

• A. C. Cem Say, M. Utkan Gezer, “Unconditional Proofs of Quantumness Between Small-Space Machines,” Quantum Information & Computation, Vol. 25, March 2025, 36-56  

B. Conference Papers

• A. C. Cem Say, Selahattin Kuru, "Nitel model tanılama," (in Turkish) Bilkon-91 1991 Bilkent Elektrik-Elektronik ve Bilgisayar Mühendisliği Konferansı, Ankara, 1991, pp. 363-366.

• A. C. Cem Say, Selahattin Kuru, "Qualitative system identification," Lecture Notes in Control and Information Sciences Vol. 180, (System Modeling and Optimization: Proceedings of the 15th IFIP Conference, Zürich, Switzerland, September 2-6, 1991),1992, pp. 657-666.

• A. C. Cem Say, Selahattin Kuru, "An extension of the corresponding value technique in qualitative modeling and simulation," Birinci Türk Yapay Zeka ve Yapay Sinir Ağları Sempozyumu, Ankara, 1992, pp.23-28.

• A. C. Cem Say, Selahattin Kuru, "QSI: Constructing models for qualitative simulation," Advances in Simulation '92 Symposium, Boğaziçi Univ., İstanbul, 1992, pp. 37-46.

• A. C. Cem Say, Selahattin Kuru, "Automatic construction of qualitative models," in Intelligent Systems: Safety, Reliability, and Maintainability Issues, Springer-Verlag, Berlin, 1993, pp. 177-193.

• Cem Say, Sidal Sen, Ruhver Barengi, "'Bir Kelime - Bir İşlem' oynayan program," (in Turkish) İkinci Türk Yapay Zeka ve Yapay Sinir Ağları Sempozyumu, İstanbul, 1993, pp. 349-355.

• İlan Berker, A. C. Cem Say, "A crossword puzzle generator for Turkish," Proceedings of the Eighth International Symposium on Computer and Information Sciences (ISCIS-VIII), İstanbul, 1993, pp. 474-477.

• Çiğdem Aytekin, A. C. Cem Say, Erkut Akçok, "ELIZA speaks Turkish: A conversation program for an agglutinative language," Üçüncü Türk Yapay Zeka ve Yapay Sinir Ağları Sempozyumu, Ankara, 1994, p. 435.

• A. C. Cem Say, "Türkçe 'anlayan' programlar," (in Turkish) TBD Bilişim '94, İstanbul, 1994, pp. 191-195.

• Metin Örsel, A. C. Cem Say, "Representing descriptions of flags," Proceedings of the Ninth International Symposium on Computer and Information Sciences (ISCIS-IX), Antalya, 1994, pp. 575-582.

• Müjdat Pakkan, A. C. Cem Say, "Qualitative collision detection in the roller coaster world," Proceedings of the Ninth International Symposium on Computer and Information Sciences (ISCIS-IX), Antalya, 1994, pp. 583-590.

• Murat Işık, A. C. Cem Say, "Qualitative noise filtering and the implementation of QF as a preprocessor to QSI," Proceedings of the Tenth International Symposium on Computer and Information Sciences (ISCIS-X), Aydın, 1995, pp. 145-152.

• A. C. Cem Say, "Functions representable in pure QSIM," Beşinci Türk Yapay Zeka ve Yapay Sinir Ağları Sempozyumu, İstanbul, 1996, pp. 251-255.

• A. C. Cem Say, "Qualitative timeline analysis," in New Trends in Artificial Intelligence and Neural Networks. EMO Scientific Books, Ankara, 1997, pp. 121-126.

• F. Canan Pembe, A. C. Cem Say, "A linguistically motivated information retrieval system for Turkish," Lecture Notes in Computer Science Vol. 3280, (Proceedings of the Nineteenth International Symposium on Computer and Information Sciences), 2004, pp. 741-750.

• Uğur Küçük, A. C. Cem Say, "Improved simulation of quantum random walks," Lecture Notes in Computer Science Vol. 3733, (Proceedings of the Twentieth International Symposium on Computer and Information Sciences), 2005, pp. 937-946.

• Abuzer Yakaryılmaz, Rūsiņš Freivalds, A. C. Cem Say, Ruben Agadzanyan, "Quantum computation with devices whose contents are never read," Lecture Notes in Computer Science Vol. 6079, (Proceedings of the 9th International Conference on Unconventional Computation), 2010, pp. 164-174.  [doi:10.1007/978-3-642-13523-1_18]

• Nuri Taşdemir, A. C. Cem Say, "Models of pushdown automata with reset," Lecture Notes in Computer Science Vol. 6795, (Proceedings of the 15th International Conference on Developments in Language Theory), 2011, pp. 417-428.

• A. C. Cem Say, Abuzer Yakaryılmaz, "Finite state verifiers with constant randomness," Lecture Notes in Computer Science Vol. 7318, How the World Computes: Turing Centenary Conference and 8th Conference on Computability in Europe, CiE 2012, Cambridge, UK, June 18-23, 2012, Proceedings, 2012, pp.646-654.

• Uğur Küçük, A. C. Cem Say, Abuzer Yakaryılmaz, "Finite automata with advice tapes," LNCS Vol. 7907, (Proceedings of the 17th International Conference on Developments in Language Theory) pp. 301-312, 2013.

• Özlem Salehi, Abuzer Yakaryılmaz, A. C. Cem Say, "Real-time vector automata," LNCS Vol. 8070, (Proceedings of the 19th International Symposium on Fundamentals of Computation Theory) pp. 293-304, 2013.

• Abuzer Yakaryılmaz, A. C. Cem Say, Gökalp Demirci, "Debates with small transparent quantum verifiers," LNCS Vol. 8633, (Proceedings of the 18th International Conference on Developments in Language Theory) pp. 327-338, 2014.

• Ryan O’Donnell, A. C. Cem Say, "One time-traveling bit is as good as logarithmically many," LIPIcs Vol. 29 (Proceedings of the 34th International Conference on Foundation of Software Technology and Theoretical Computer Science) pp. 469-480, 2014. http://eccc.hpi-web.de/report/2014/091

• Cafer Caferov, Barış Kaya, Ryan O’Donnell, A. C. Cem Say, "Optimal bounds for estimating entropy with PMF queries," LNCS Vol. 9235, (Proceedings of the 40th International Symposium on Mathematical Foundations of Computer Science) pp. 187-198, 2015.

• Özlem Salehi, Flavio D’Alessandro, A. C. Cem Say, “Generalized results on monoids as memory,” E. Csuhaj-Varjú, P. Dömösi, Gy. Vaszil (Eds.): 15th International Conference on Automata and Formal Languages (AFL 2017) EPTCS 252, 2017, pp. 234–247, doi:10.4204/EPTCS.252.22

• Öykü Yılmaz, Fırat Kıyak, Meriç Üngör, A. C. Cem Say, “Energy complexity of regular language recognition”, LNCS Vol. 13266, Implementation and Application of Automata (26th International Conference, CIAA 2022 Proceedings) pp. 200-211, 2022.

• Özdeniz Dolu, Nevzat Ersoy, M. Utkan Gezer, A. C. Cem Say, “Real-time, constant-space, constant-randomness verifiers”, LNCS Vol. 13266, Implementation and Application of Automata (26th International Conference, CIAA 2022 Proceedings) pp. 212-224, 2022.

• Ahmet Celal Cem Say, “Energy complexity of computation”, LNCS Vol. 13960, Reversible Computation (15th International Conference, RC 2023 Proceedings) pp. 3-11, 2023.

C. Technical Reports and Manuscripts

• Reha Kamil Gerçeker, A. C. Cem Say, "Using polynomial approximations to discover qualitative models," Proceedings of the 20th International Workshop on Qualitative Reasoning. Editors: Chris Bailey-Kellogg and Benjamin Kuipers, pp. 71-80, Darthmouth College, Hanover, New Hampshire, USA, 2006.

• Nuri Taşdemir, A. C. Cem Say, "Provably spurious qualitative simulation predictions that just won’t go away," Proceedings of the 21st International Workshop on Qualitative Reasoning. Editor: Chris Price, pp. 170-180, Aberystwyth, UK, 2007.

• Abuzer Yakaryılmaz, A. C. Cem Say, "Language recognition by generalized quantum finite automata with unbounded error," 4th Workshop on Theory of Quantum Computation, Communication, and Cryptography, TQC2009, Waterloo, Ontario, Canada, 2009. (arXiv:0901.2703).

• Abuzer Yakaryılmaz, A. C. Cem Say, "NP has log-space verifiers with fixed-size public quantum registers," (8th Central European Quantum Information Processing Workshop), 2011. [arXiv:1101.5227] 

• Gökalp Demirci, Mika Hirvensalo, Klaus Reinhardt, A. C. Cem Say, Abuzer Yakaryılmaz, "Classical and quantum realtime alternating automata," 6th International Workshop on Non-Classical Models of Automata and Applications, 2014. (arXiv: 1407.0334)

• A. C. Cem Say, Abuzer Yakaryılmaz, "Magic coins are useful for small-space quantum machines," http://eccc.hpi-web.de/report/2014/159/

• Özlem Salehi, A. C. Cem Say, "Homing vector automata," 7th International Workshop on Non-Classical Models of Automata and Applications, 2015. (arXiv:1504.04859)

• Uğur Küçük, A. C. Cem Say, Abuzer Yakaryılmaz, "Inkdots as advice to small-space machines," arXiv:1509.03712.

• Özlem Salehi, Ahmet Celal Cem Say, “Extended finite automata and decision problems for matrix semigroups”, Tenth Workshop on Non-Classical Models of Automata and Applications, NCMA 2018 (21.08-22.08)

• Öykü Yılmaz, Fırat Kıyak, Meriç Üngör, A. C. Cem Say, “Energy complexity of regular language recognition”, arXiv:2204.06025 [cs.CC]

• Fırat Kıyak, A. C. Cem Say, “Read-once machines and the thermodynamic complexity of Maxwell’s demons”, arXiv:2304.11452 [cs.IT]

• Fırat Kıyak, A. C. Cem Say, “Energy complexity of regular languages”, arXiv:2204.06025v2 [cs.CC]

• M. Utkan Gezer, A. C. Cem Say, “P has polynomial-time finite-state verifiers”, https://arxiv.org/abs/2306.09542

• A. C. Cem Say, "Time hierarchies for sublogarithmic-space quantum computation" 2025, arXiv: 2503.21582

• A. C. Cem Say, "Short and useful quantum proofs for sublogarithmic-space verifiers" 2025, arXiv: 2505.08462

D. Books

1. M. Ufuk Çağlayan, Fedon Kadifeli, A. C. Cem Say. Standard C Programming. Boğaziçi University Publications, 1989.

2. Fedon Kadifeli, A. C. Cem Say, M. Ufuk Çağlayan. Standart C Programlama Dili (in Turkish). Sarmal Yayınları, 1993. (Translated and updated from (1) by F. Kadifeli.)

3. Cem Say, 50 Soruda Yapay Zekâ. Bilim ve Gelecek Kitaplığı, 2018

4. Cem Say, Yeni Dünya, Yeni Ağ. Destek Yayınları, 2020

5. Cem Say, En Hakiki Mürşit. Doğan Kitap, 2021

6. Cem Say, Sedat Yalçın, Bahadır Yıldız, Yapay Zekâya Giriş. Hisar Eğitim Vakfı Yayınları, 2023

E. Edited Volumes

1. Selahattin Kuru, H. Levent Akın, A. C. Cem Say, Ethem Alpaydın (Eds.). İkinci Türk Yapay Zeka ve Yapay Sinir Ağları Sempozyumu Bildiriler. Boğaziçi Üniversitesi, İstanbul, 1993.

2. A. C. Cem Say, Günhan Dündar (Eds.) Proceedings of the Eighth Turkish Symposium on Artificial Intelligence and Neural Networks. Boğaziçi Üniversitesi, İstanbul, 1999.

F. Miscellaneous

1. A. C. Cem Say, "Sen de mi şair oldun ey bilgisayar?" Çağrı Dergisi, no. 400, 1993, p. 9.

2. A. C. Cem Say, "Sıcak bir TAINN günü" Beşinci Türk Yapay Zeka ve Yapay Sinir Ağları Sempozyumu, İstanbul, 1996, p. 381.

3. Cem Say, "Akla doğru" Cogito, no. 13, 1998, pp. 67-74.

4. Cem Say, "Gödel’in eksiklik teoremi" Matematik Dünyası, Yıl 14, Sayı 4, 2005, 67-71.

5. Cem Say, "Nitel benzetim" Türkiye Bilişim Ansiklopedisi. TBV-Papatya Yayıncılık Eğitim, 611-615, 2006.

6. Cem Say, "Yapay zeka, doğal zeka ve özgürlük" Bilim ve Ütopya, Yıl 18, Sayı 220, 2012, 42-48.

7. A. C. Cem Say, "Diller, çözümsüz problemler ve sonsuzluk" Bilgisayar ve Beyin: "Bilgi İşleyen Makine Olarak Beyin" Toplantıları, yayına hazırlayan: Haluk Bingöl, Pan Yayıncılık, 177-184, 2012.

8. Cem Say, "Yapay zeka ve Gödel teoremi" Bilgisayar ve Beyin: "Bilgi İşleyen Makine Olarak Beyin" Toplantıları, yayına hazırlayan: Haluk Bingöl, Pan Yayıncılık, 254-264, 2012.

9. A. C. Cem Say, Abuzer Yakaryılmaz, "Quantum finite automata: A modern introduction," Computing with New Resources, LNCS Vol. 8808, (Essays Dedicated to Josef Gruska on the Occasion of His 80th Birthday) pp. 208-222, 2014. arXiv: 1406:4048

Doctoral Dissertation: Qualitative System Identification. Boğaziçi University, 1992. (First thesis of Boğaziçi’s Computer Engineering PhD program)