A topological space in which any two points can be joined by a continuous path (a continuous map from the unit interval [0,1] into the space whose endpoints are the two points).

Principle

Connectivity strengthened by existence of continuous paths between points: the topology admits continuous parameterized arcs linking any pair of points.

Demonstration

Euclidean space R^n is path‑connected because for any two points one can take the straight line segment parameterized by t ↦ (1−t)x + t y, a continuous path entirely contained in R^n.

Misapplication

Assuming path‑connectedness implies simple connectivity or that images of paths are open; path‑connectedness does not control loop contraction or local openness of path images.

Consequence

Path components partition the space into maximal path‑connected subsets; in locally path‑connected spaces path components are open and path‑connectedness implies connectedness, aiding algebraic topology constructions like the fundamental group.

Reversal

A space may be connected but not path‑connected (example: the topologist's sine curve), so lack of path‑connectedness means some pairs cannot be joined by continuous paths despite no separation into two open sets.

Boundary

Depends on continuous maps from [0,1]; it is a stronger condition than mere connectedness and different from higher homotopy or homology properties; local path‑connectedness or manifold structure often alters consequences.

Semantic Tension

Tension with connectedness: connectedness forbids separation into disjoint open sets but allows spaces without paths between points; path‑connectedness requires explicit continuous links and is strictly stronger in general.

Synthesis

Path‑connectedness requires a continuous path between every pair of points, producing path components that refine connected components and enabling constructive homotopy arguments while remaining logically distinct from higher homotopy or simple connectivity.