Metamath Proof Explorer


Definition df-propimp

Description: The implication between two sentences of propositional calculus is encoded by concatenating the two sentences and appending a two at the end. (Contributed by Thomas van Maaren, 21-Aug-2026)

Ref Expression
Assertion df-propimp prop→ = ( 𝑥 ∈ V , 𝑦 ∈ V ↦ ( ( 𝑥 ++ 𝑦 ) ++ ⟨“ 2 ”⟩ ) )

Detailed syntax breakdown

Step Hyp Ref Expression
0 cpropimp prop→
1 vx 𝑥
2 cvv V
3 vy 𝑦
4 1 cv 𝑥
5 cconcat ++
6 3 cv 𝑦
7 4 6 5 co ( 𝑥 ++ 𝑦 )
8 c2 2
9 8 cs1 ⟨“ 2 ”⟩
10 7 9 5 co ( ( 𝑥 ++ 𝑦 ) ++ ⟨“ 2 ”⟩ )
11 1 3 2 2 10 cmpo ( 𝑥 ∈ V , 𝑦 ∈ V ↦ ( ( 𝑥 ++ 𝑦 ) ++ ⟨“ 2 ”⟩ ) )
12 0 11 wceq prop→ = ( 𝑥 ∈ V , 𝑦 ∈ V ↦ ( ( 𝑥 ++ 𝑦 ) ++ ⟨“ 2 ”⟩ ) )