 Thom's first isotopy lemma

Thom's first isotopy lemma is a result in the field of topology, specifically in the theory of stable homotopy and cobordism. It is named after the mathematician René Thom and deals with the properties of smooth manifolds and isotopies. In simplified terms, Thom's first isotopy lemma states that if you have two smooth maps from a manifold \( M \) into another manifold \( N \), and if these maps are homotopic (i.e.