Essays in Heterogeneous Learning

5 Abstract Essays in Heterogeneous Learning by Anna Bogomolova My dissertation makes a contribution to the …eld of heterogeneous adaptive learning in macroeconomic models. This contribution is presented in the form of three research papers that constitute di¤erent chapters of my thesis. In the …rst chapter of my dissertation, "E-stability That Does Imply Learnability", I provide criteria and su¢ cient conditions for the stability of a structurally heterogeneous economy under the heterogeneous learning of agents, extending the results of Honkapohja and Mitra [36], Bogomolova and Kolyuzhnov [5], and Kolyuzhnov [40]. I provide general criteria (in terms of the corresponding Jacobian matrices) for stability under heterogeneous mixed RLS/SG learning for four classes of models: models without lags and with lags of the endogenous variable and with t- or t 1- dating of expectations, and provide su¢ cient conditions for stability for some simpler cases, where simpli…cations include either the diagonal structure of the shock process behaviour or the heterogeneous RLS learning. I also provide su¢ cient conditions for stability in terms of the structural heterogeneity independent of heterogeneity in learning ( -stability) in terms of E-stability of a suitably de…ned aggregate economy for all four classes of models..