Description: A singleton word is a word. (Contributed by Mario Carneiro, 26-Feb-2016)
Ref | Expression | ||
---|---|---|---|
Assertion | s1cli | ⊢ ⟨“ 𝐴 ”⟩ ∈ Word V |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ids1 | ⊢ ⟨“ 𝐴 ”⟩ = ⟨“ ( I ‘ 𝐴 ) ”⟩ | |
2 | fvex | ⊢ ( I ‘ 𝐴 ) ∈ V | |
3 | s1cl | ⊢ ( ( I ‘ 𝐴 ) ∈ V → ⟨“ ( I ‘ 𝐴 ) ”⟩ ∈ Word V ) | |
4 | 2 3 | ax-mp | ⊢ ⟨“ ( I ‘ 𝐴 ) ”⟩ ∈ Word V |
5 | 1 4 | eqeltri | ⊢ ⟨“ 𝐴 ”⟩ ∈ Word V |