How statement and proof provenance work
The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.
- Literature-sourced: the exact statement appears in a cited source; only wording and notation differ.
- AI-adapted: a semantically identical restatement of literature-sourced material, modulo indexing, notation, and boundary cases adopted by the library.
- AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.
These labels describe origin, not correctness: citations and verification chips remain separate evidence.
is polygonally connected, connected, locally path-connected and locally connected
Statement
For , is polygonally connected and connected, and it is locally path-connected and locally connected.
Facts & Assumptions
Given: with and its Euclidean topology.
A segment is a continuous polygonal path in (A finite concatenation of straight segments in is a continuous path, Polygonal paths and polygonally connected subsets of ).
Euclidean balls are open and every open neighbourhood contains a Euclidean ball about its point (Open ball, closed ball and sphere in a metric space, The metric topology: a set is open when every one of its points has a ball around it inside the set; closed means open complement).
Every path-connected space is connected, and every locally path-connected space is locally connected (Every path-connected space is connected, and every path component lies inside a component, Locally connected and locally path-connected spaces: a neighbourhood base of open connected, respectively open path-connected, sets at every point).
The norm triangle inequality keeps a segment joining two points of an open ball inside that ball (A norm on a real vector space, the induced metric, and the dictionary with the metric axioms).
Proof
For , the one-segment path joins them. Hence is polygonally connected.
Let and let be open with . Choose with . Each pair of points in this ball is joined by its segment, which stays in the ball by [L4].
It is path-connected and therefore connected by [L3].
Thus every open neighbourhood contains an open path-connected ball, so is locally path-connected, and it is locally connected by [L3].
Depends on
Polygonal paths and polygonally connected subsets of
A finite concatenation of straight segments in is a continuous path
Every path-connected space is connected, and every path component lies inside a component
Locally connected and locally path-connected spaces: a neighbourhood base of open connected, respectively open path-connected, sets at every point
Open ball, closed ball and sphere in a metric space
A norm on a real vector space, the induced metric, and the dictionary with the metric axioms
The metric topology: a set is open when every one of its points has a ball around it inside the set; closed means open complement