More on orthogonality in locally presentable categories (Q2719722)

The authors investigate orthogonal subcategories of locally presentable categories by means of a new tool, called ``non-standard orthogonal-reflection construction''. Their main result characterizes the \(\omega\)-orthogonality classes in a locally finitely presentable category \(\mathcal C\) as those full subcategories \(\mathcal A\) of \(\mathcal C\) that are closed under the formation of limits and filtered colimits in \(\mathcal C\) and for which the theory of the embedding \({\mathcal A} \hookrightarrow {\mathcal C}\) is a quotient. The paper also contains several interesting applications and generalizations.