Nusc
- 752
- 2
Homework Statement
Let [tex]f: M \rightarrow N[/tex], [tex]g:N \rightarrow K[/tex], and [tex]h = g \circ f : M \rightarrow K[/tex]. Show that [tex]h_{*} = g_{*} \circ f_{*}[/tex].
Proof:
Let [tex]M[/tex],[tex]N[/tex] and [tex]K[/tex] be manifolds and [tex]f[/tex] and [tex]g[/tex] be [tex]C^\infinity[/tex] functions.
Let [tex]p \in M[/tex]. For any [tex]u \in F^{\infinity}(g(f((p)))[/tex] and any derivation [tex]D[/tex] at [tex]p[/tex].
[tex][g \circ f)_* D](u) = D(u \circ g \circ f) = (f_{*}D)(u \circ g) = (g_{*}(f_{*}D))(u)[/tex]