Metamath Proof Explorer


Theorem efcld

Description: Closure law for the exponential function, deduction version. (Contributed by Thierry Arnoux, 1-Dec-2021)

Ref Expression
Hypothesis efcld.1 φ A
Assertion efcld φ e A

Proof

Step Hyp Ref Expression
1 efcld.1 φ A
2 efcl A e A
3 1 2 syl φ e A