Add concrete category

trees/tt-0053.tree

@@ -0,0 +1,17 @@
+\import{tt-macros}
+% clifford hopf spin tt math draft
+\tag{tt}
+\tag{draft}
+
+% definition theorem lemma construction observation
+% convention corollary axiom example exercise proof
+% discussion remark notation
+% \taxon{}
+% \taxon{lemma}\refnotet{}{}{}{
+
+% kostecki2011introduction leinster2016basic nakahira2023diagrammatic rosiak2022sheaf
+
+\refdeft{concrete category}{1.6.17}{riehl2017category}{
+\p{A \newvocab{concrete category} is a category #{\C} equipped with a \vocabk{faithful}{tt-0017} functor #{\fF : \C \to \Set}.
+}
+}