Metamath Proof Explorer


Theorem dvnbss

Description: The set of N-times differentiable points is a subset of the domain of the function. (Contributed by Stefan O'Rear, 16-Nov-2014) (Revised by Mario Carneiro, 11-Feb-2015)

Ref Expression
Assertion dvnbss SF𝑝𝑚SN0domSDnFNdomF

Proof

Step Hyp Ref Expression
1 dvnff SF𝑝𝑚SSDnF:0𝑝𝑚domF
2 1 ffvelcdmda SF𝑝𝑚SN0SDnFN𝑝𝑚domF
3 2 3impa SF𝑝𝑚SN0SDnFN𝑝𝑚domF
4 cnex V
5 simp2 SF𝑝𝑚SN0F𝑝𝑚S
6 5 dmexd SF𝑝𝑚SN0domFV
7 elpm2g VdomFVSDnFN𝑝𝑚domFSDnFN:domSDnFNdomSDnFNdomF
8 4 6 7 sylancr SF𝑝𝑚SN0SDnFN𝑝𝑚domFSDnFN:domSDnFNdomSDnFNdomF
9 3 8 mpbid SF𝑝𝑚SN0SDnFN:domSDnFNdomSDnFNdomF
10 9 simprd SF𝑝𝑚SN0domSDnFNdomF