[004L] ExerciseLet TTT be a base type theory. We work in TTT. Then the function X↦mX:SubTop→LAMX\mapsto \mathord {\textnormal {\textsf {m}}}_{X}:\mathord {\textnormal {\textsf {SubTop}}}\rightarrow \mathord {\textnormal {\textsf {LAM}}}X↦mX:SubTop→LAM is an equivalence.