Mathematical Researches

fa انشعابات هم بعد-2 سیستم گسسته‌ی شکار و شکار‌چی the predator-prey discrete system codimention- 2 bifurcations جبر alg علمی پژوهشی کاربردی S در این مقاله به بررسی رفتار‌های دینامیکی یک سیستم گسسته‌ی شکار و شکارچی می‌پردازیم. وجود و پایداری نقاط ثابت سیستم را بررسی می‌کنیم و شرایط کافی برای وجود انشعاب فیلیپ و نایمارک-ساکر را ارائه می‌دهیم. با استفاده از روش‌های عددی انشعاب و جعبه ابزار  MatContMخمهای انشعاب نقطه ثابت از قبیل خم‌ انشعاب نایمارک-ساکر را به همراه نقاط انشعاب روی این خم‌ها به‌دست آورده و  سیکل‌های تا تکرار 32 را محاسبه می‌کنیم. تمام انشعابات همبعد-1 و همبعد-2 و سوئیچ  انشعابهای ‌همبعد2 را هم محاسبه میکنیم و در نهایت با استفاده از شبیهسازی عددی رفتار آشوبی سیستم را نمایش میدهیم.   Introduction   In population dynamics, discrete-time dynamical systems have been used to describe interaction between ecological species. Comparing to continuous-time dynamical systems, discrete-time models are more suitable to describe populations with non overlapping generations. These models in general produce rich and complex dynamical behaviors. Among various population interaction, predator-prey models play a fundamental rule in mathematical ecology. The dynamics of predator-prey system is greatly depend on the implementation of the functional response, the availability of prey for predation. In this paper we consider a planar system which describes a predator-prey model. In order to reveal comprehensive dynamics of the system, we employee theoretical tools such as center manifold theorem along with numerical tools based on numerical continuation method.  Material and methods Our analysis is based on theoretical and numerical techniques. We first determine all fixed points of the system and conditions under which these points may undergo different bifurcations. To reveal more dynamics of the system, we also use numerical bifurcation methods and numerical simulations, which further examine the obtained analytical results. Results and discussion For the resented discrete-time predator-prey system, we compute several bifurcation curves, all possible codimension-1 and codimension-2 bifurcations on thses curves along with their corresponding normal form coefficients. By branch switching technique and employing software package MatcontM, we compute stability boundaries for several cycles up to period 32. We also use numerical simulation, to compute basin of attraction and strange attractor emerging around a Neimark-Sacker bifurcation.  Conclusion We can highlight the following results from this paper. <ul> <li style="margin-bottom:13px; margin-left:32px; text-align:justify">Detection and location of all fixed points of a discrete-time predator pray system.</li> <li style="margin-bottom:13px; margin-left:32px; text-align:justify">Computing all possible codimension-1 and -2 bifurcation and their corresponding normal form coefficients which in turn reveal criticality of the bifurcation points and determine if extra bifurcation curves can emanate from each detected bifurcation.</li> <li style="margin-bottom:13px; margin-left:32px; text-align:justify">Computing orbits up to period 32 which determine stability thresholds for different cycles.</li> </ul> Computing basin of attraction and strange of attractor which emerge around a Neimark-Sacker bifurcation by means of numerical simulation technique.   نقطه ثابت, انشعاب, پایداری, شبیه سازی عددی Fixed point,Bifurcation,Stability,Numerical simulation 216 241 http://mmr.khu.ac.ir/browse.php?a_code=A-10-973-1&slc_lang=fa&sid=1 raana moghadasi رعنا مقدسی raana.moghadasi.brn@gmail.com 10031947532846005481 10031947532846005481 Yes shahrekorduniversity دانشگاه شهرکرد reza khoshsiar رضا خوش سیر rkhoshsiar@gmail.com 10031947532846005482 10031947532846005482 No shahrekorduniversity دانشگاه شهرکرد