Metamath Proof Explorer


Theorem deccl

Description: Closure for a numeral. (Contributed by Mario Carneiro, 17-Apr-2015) (Revised by AV, 6-Sep-2021)

Ref Expression
Hypotheses deccl.1 ⊢ A ∈ ℕ 0
deccl.2 ⊢ B ∈ ℕ 0
Assertion deccl Could not format assertion : No typesetting found for |- ; A B e. NN0 with typecode |-

Proof

Step Hyp Ref Expression
1 deccl.1 ⊢ A ∈ ℕ 0
2 deccl.2 ⊢ B ∈ ℕ 0
3 df-dec Could not format ; A B = ( ( ( 9 + 1 ) x. A ) + B ) : No typesetting found for |- ; A B = ( ( ( 9 + 1 ) x. A ) + B ) with typecode |-
4 9nn0 ⊢ 9 ∈ ℕ 0
5 1nn0 ⊢ 1 ∈ ℕ 0
6 4 5 nn0addcli ⊢ 9 + 1 ∈ ℕ 0
7 6 1 2 numcl ⊢ 9 + 1 ⁢ A + B ∈ ℕ 0
8 3 7 eqeltri Could not format ; A B e. NN0 : No typesetting found for |- ; A B e. NN0 with typecode |-