A MODEL ON MARKET EQUILIBRIUM USING A DIFFERENTIAL EQUATION WITH TIME DELAYS
Abstract
In this paper, a model on market equilibrium is proposed using a delay differential equation with discrete delays as a modified version of the one proposed by Kobayashi (1996). The price of a commodity is determined using the equation involving weighted supply and demand functions. Both supply and demand functions are considered at the current time and sometimes in the past. The delays are chosen by considering the seasonal behavior of the market. We use data on some main commodities in Indonesia from 2018 to 2024 to validate the model. We found that the implementation of our modified Kobayashi model improves the estimation given by the original one. The implementation of the method also shows some characteristics of delay equations, that is longer delay time may include more dynamics, and more fluctuation, although that means it is more prone to instabilities. However, the problem of optimal delay time is yet to be resolved.
Downloads
References
Rihan, F. A. (2021). DELAY DIFFERENTIAL EQUATIONS AND APPLICATIONS TO BIOLOGY. Springer. https://doi.org/10.1007/978-981-16-0626-7
Polyanin, A. D., Sorokin, V. G., & Zhurov, A. I. (2021). DELAY ORDINARY AND PARTIAL DIFFERENTIAL EQUATIONS. CRC Press.
Xie, Y., Zhang, Z., Wu, Y., Li, S., Pang, L., & Li, Y. (2024). TIME-DELAY DYNAMIC MODEL AND COST-EFFECTIVENESS ANALYSIS OF MAJOR EMERGENT INFECTIOUS DISEASES WITH TRANSPORTATION-RELATED INFECTION AND ENTRY-EXIT SCREENING. Mathematics, 12(13), 2069. https://doi.org/10.3990/math12132069
Wang, X., & Wang, H. (2022). CONTEMPORARY DELAY DIFFERENTIAL EQUATION MODELS AND ANALYSIS IN MATHEMATICAL BIOLOGY. In Contemporary Research in Mathematical Biology – Modeling, Computation and Analysis, World Scientific.
Matsumoto, A., Ferenc Szidarovszky, F., Asada, T. (2016). ESSAYS IN ECONOMIC, DYNAMICS, THEORY, SIMULATION ANALYSIS, AND METHODOLOGICAL STUDY. Springer.
Samuelson, P. A., & Nordhaus, W. D. (2009). ECONOMICS (9th ed.). McGraw-Hill.
Giorgi, G., Jiménez, B., & Novo, V. (2025). LECTURES ON MATHEMATICS FOR ECONOMIC AND FINANCIAL ANALYSIS. Springer.
Arutyunov, A. V., & Pavlova, N. G. (2022). EQUILIBRIUM IN MARKET MODELS DESCRIBED BY DIFFERENTIAL EQUATIONS. Differential Equations, 58(9), 1267–1276. https://doi.org/10.1134/S0012266122090117
Szydłowski, M., & Krawiec, A. (2021). COMPLEX DYNAMICS OF ECONOMIC MODELS WITH TIME DELAY. In D. Grech & J. Miśkiewicz, (Eds.), Simplicity of complexity in economic and social systems. Springer. https://doi.org/10.1007/978-3-030-56160-4_6
Martina, B., & Veronika, N. (2015). The use of functional differential equations in the model of the meat market with supply delay. Procedia–Social and Behavioral Sciences, 213, 74–79. https://doi.org/10.1016/j.sbspro.2015.11.406
Matsumoto, A., & Szidarovszky, F. (2010). DELAY DIFFERENTIAL NONLINEAR ECONOMIC MODELS. Nonlinear Dynamics in Economics, Finance and Social Sciences: Essays in Honour of John Barkley Rosser Jr, Finance and Social Sciences, 195–214. https://doi.org/10.1007/978-3-642-04023-8
Anokye, M., Barnes, B., Ohene Boateng, F., Adom-Konadu, A., & Amoah-Mensah, J. (2023). PRICE DYNAMICS OF A DELAY DIFFERENTIAL COBWEB MODEL. Discrete Dynamics in Nature and Society, 2023. https://doi.org/10.1155/2023/1296562
Kobayashi, K. (1996). AN APPLICATION OF DELAY DIFFERENTIAL EQUATIONS TO MARKET EQUILIBRIUM. RMIS Kokyuroku, Kyoto University 940, 12-16. https://www.kurims.kyoto-u.ac.jp/~kyodo/kokyuroku/contents/pdf/0940-3.pdf
Gopalsanny, K. (1992). STABILITY AND OSCILLATIONS IN DELAY DIFFERENTIAL EQUATIONS OF POPULATION DYNAMICS. Springer Science+Business Media.
Liu, K. , Laine, I., and Yang, L. (2021). COMPLEX DELAY-DIFFERENTIAL EQUATIONS. De Gruyter Studies in Mathematics, De Gruyter. https://doi.org/10.1515/9783110560565
Mitsui, T., Hu, G-D. (2023). NUMERICAL ANALYSIS OF ORDINARY AND DELAY DIFFERENTIAL EQUATIONS. Springer.
Harsono, N. (2022, May 27). MINISTRY ISSUES DETAILED POLICY ON PALM OIL EXPORTS. The Jakarta Post. https://www.thejakartapost.com/paper/2022/05/26/ministry-issues-detailed-policy-on-palm-oil-exports.html
Girardin, V., Limnios, N. (2022). APPLIED PROBABILITY: FROM RANDOM EXPERIMENTS TO RANDOM SEQUENCES AND STATISTICS. Springer.
Lange, K. (2024). APPLIED PROBABILITY (3rd ed.). Springer Texts in Statistics. Springer.
Walpole, R. E., Myers, R. H., Myers, S. L., & Ye, K. (2017). PROBABILITY AND STATISTICS FOR ENGINEERS AND SCIENTISTS. Pearson.
Zamelina, A., Astutik, S., Fitriani, R., Fernandes, A., & Ramifidisoa, L. (2024). ENHANCING WEIGHTED FUZZY TIME SERIES FORECASTING THROUGH PARTICLE SWARM OPTIMIZATION. BAREKENG: Journal of Mathematics and Applications, 18(4), 2675-2684. https://doi.org/10.30598/barekengvol18iss4pp2675-2684
Liputan6. (2022, December 1). HARGA TELUR AYAM MERANGKAK NAIK SEJAK MARET 2022: INI BIANG KEROKNYA. Liputan6. https://www.liputan6.com/bisnis/read/5141531/harga-telur-ayam-merangkak-naik-sejak-maret-2022-ini-biang-keroknya
Dalimunthe, D., Kustiawan, E., Halim, N., and Suhendra, H. (2025). VOLATILITY ANALYSIS AND INFLATION PREDICTION IN PANGKALPINANG USING ARCH GARCH MODEL. BAREKENG: Journal of Mathematics and Applications, 19(1), 237-244. https://doi.org/10.30598/barekengvol19iss1pp237-244
Copyright (c) 2025 Jalina Widjaja, Naufal Zidan Putra Irawan, Yudi Soeharyadi, Dumaria R. Tampubolon

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Authors who publish with this Journal agree to the following terms:
- Author retain copyright and grant the journal right of first publication with the work simultaneously licensed under a creative commons attribution license that allow others to share the work within an acknowledgement of the work’s authorship and initial publication of this journal.
- Authors are able to enter into separate, additional contractual arrangement for the non-exclusive distribution of the journal’s published version of the work (e.g. acknowledgement of its initial publication in this journal).
- Authors are permitted and encouraged to post their work online (e.g. in institutional repositories or on their websites) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published works.