{"id":4420,"date":"2019-04-11T09:06:42","date_gmt":"2019-04-11T16:06:42","guid":{"rendered":"http:\/\/blogs.pugetsound.edu\/econ\/?p=4420"},"modified":"2019-04-11T09:06:42","modified_gmt":"2019-04-11T16:06:42","slug":"dynamic-stability-and-recursion","status":"publish","type":"post","link":"https:\/\/blogs.pugetsound.edu\/econ\/2019\/04\/11\/dynamic-stability-and-recursion\/","title":{"rendered":"Dynamic Stability and Recursion"},"content":{"rendered":"<p><span style=\"font-weight: 400;\">Economics and computer science overlap in surprising frequency. \u00a0Most of it is computational; calculating equilibrium, maximizing profit, etc. \u00a0Computer science has even integrated into economics through R. Comp sci can make things easier and there\u2019s a wide range of economic applications. \u00a0Recently I observed one of these applications. It began when I was studying for my computer science test There was a subject on this test called recursion. \u00a0In practice recursion is very difficult, and as any students know, just because you take a test on it, doesn\u2019t mean you understand it.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">While the application can be difficult, the concept is not as complicated. \u00a0The idea behind recursion is an action, that is repeated itself. An example is multiplication, when I say 4&#215;3 what I\u2019m also saying is 4+4+4. \u00a0If I wanted to solve this recursively I would take the following steps.<\/span><\/p>\n<ol>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">4+4+4<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">8+4<\/span><\/li>\n<li style=\"font-weight: 400;\"><span style=\"font-weight: 400;\">12<\/span><\/li>\n<\/ol>\n<p><span style=\"font-weight: 400;\">Similar methods can be used to solve exponents, addition and much more. \u00a0If you\u2019re a visual learner, then I suggest looking at the graphical methods below to get a better idea of recursion. \u00a0While I was studying recursion we where reviewing Cournot duopolies in my math-econ class (best response functions). A best response function is a function that calculates a firms best response to another firms choice in price or quantity. \u00a0Usually in these equations you can solve for an nash equilibrium. A nash equilibrium is when neither firms would have any incentive to deviate from a price* or quantity*.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">However, similar to simple supply and demand, these equilibrium can have dynamic stability. \u00a0If one firm chooses a p or q outside of equilibrium the decisions will gravitate toward equilibrium. \u00a0It does this by each firm best responding to the other firm\u2019s out of equilibrium decision. Mathematically, it requires recalculating the firm\u2019s best response function. \u00a0This is a recursive concept. In order to arrive at the nash equilibrium you have to calculate BR over and over and over again until it converges.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Another aspect of recursion is getting them to stop. \u00a0There are a few simple ways to get a method to stop; one way is specifying an amount of repetitions like 5 or 10,000, another way is by making a convergence constraint. \u00a0This is when the answer is changing from step to step. It is more applicable in this case to use the latter. When observing dynamic stability it never exactly reaches equilibrium, it just gets really really close. \u00a0Therefore you can\u2019t stop when it hits equilibrium, you have to stop for another reason.<\/span><\/p>\n<p><span style=\"font-weight: 400;\"><a href=\"http:\/\/blogs.pugetsound.edu\/econ\/files\/2019\/04\/images.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone  wp-image-4424\" src=\"http:\/\/blogs.pugetsound.edu\/econ\/files\/2019\/04\/images.png\" alt=\"\" width=\"340\" height=\"274\" \/><\/a><a href=\"http:\/\/blogs.pugetsound.edu\/econ\/files\/2019\/04\/Screen-Shot-2019-04-09-at-11.59.03-AM-1.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone  wp-image-4422\" src=\"http:\/\/blogs.pugetsound.edu\/econ\/files\/2019\/04\/Screen-Shot-2019-04-09-at-11.59.03-AM-1-300x296.png\" alt=\"\" width=\"280\" height=\"277\" srcset=\"https:\/\/blogs.pugetsound.edu\/econ\/files\/2019\/04\/Screen-Shot-2019-04-09-at-11.59.03-AM-1-300x296.png 300w, https:\/\/blogs.pugetsound.edu\/econ\/files\/2019\/04\/Screen-Shot-2019-04-09-at-11.59.03-AM-1.png 583w\" sizes=\"auto, (max-width: 280px) 100vw, 280px\" \/><\/a><a href=\"http:\/\/blogs.pugetsound.edu\/econ\/files\/2019\/04\/images.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone  wp-image-4423\" src=\"http:\/\/blogs.pugetsound.edu\/econ\/files\/2019\/04\/images-300x48.jpg\" alt=\"\" width=\"618\" height=\"110\" \/><\/a><\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Economics and computer science overlap in surprising frequency. \u00a0Most of it is computational; calculating equilibrium, maximizing profit, etc. \u00a0Computer science has even integrated into economics through R. Comp sci can make things easier and there\u2019s a wide range of economic applications. \u00a0Recently I observed one of these applications. It began when I was studying for my computer science test There was a subject on this test called recursion. \u00a0In practice recursion is very difficult, and as any students know, just because you take a test on it, doesn\u2019t mean you understand it. While the application can be difficult, the concept <a class=\"more-link\" href=\"https:\/\/blogs.pugetsound.edu\/econ\/2019\/04\/11\/dynamic-stability-and-recursion\/\">Continue reading <span class=\"screen-reader-text\">  Dynamic Stability and Recursion<\/span><span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":581,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[],"class_list":["post-4420","post","type-post","status-publish","format-standard","hentry","category-economics"],"_links":{"self":[{"href":"https:\/\/blogs.pugetsound.edu\/econ\/wp-json\/wp\/v2\/posts\/4420","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.pugetsound.edu\/econ\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.pugetsound.edu\/econ\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.pugetsound.edu\/econ\/wp-json\/wp\/v2\/users\/581"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.pugetsound.edu\/econ\/wp-json\/wp\/v2\/comments?post=4420"}],"version-history":[{"count":1,"href":"https:\/\/blogs.pugetsound.edu\/econ\/wp-json\/wp\/v2\/posts\/4420\/revisions"}],"predecessor-version":[{"id":4425,"href":"https:\/\/blogs.pugetsound.edu\/econ\/wp-json\/wp\/v2\/posts\/4420\/revisions\/4425"}],"wp:attachment":[{"href":"https:\/\/blogs.pugetsound.edu\/econ\/wp-json\/wp\/v2\/media?parent=4420"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.pugetsound.edu\/econ\/wp-json\/wp\/v2\/categories?post=4420"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.pugetsound.edu\/econ\/wp-json\/wp\/v2\/tags?post=4420"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}