1. e : EuclideanPlane@i'
2. a : Point@i
3. b : Point@i
4. X = |ab| ∈ {p:Point| O_X_p} @i
⊢ a = b ∈ Point
{ Unfold `eu-length` 4 }
1. e : EuclideanPlane@i'
2. a : Point@i
3. b : Point@i
4. X = (extend OX by ab.1ab.2) ∈ {p:Point| O_X_p} @i
⊢ a = b ∈ Point