Abstract
Let ℍ be the so-called Hawaiian earring, i.e., ℍ = {(x,y): (x-1/n)2+y2 = 1/n2, 1 ≤ n ≤ ω} and o = (0,0). We prove: (1) If Y is a subspace of a line in the Euclidean plane ℝ2 and X its complement ℝ2\Y with x ∈ X, then the fundamental group π1(X, x) is isomorphic to a subgroup of π1(ℍ, o). (2) Let Y be a subspace of a line in the Euclidean plane ℝ2. Then, π1(ℝ2\Y, x) for x ∈ ℝ2\Y is isomorphic to π1(ℍ, o), if and only if there exists infinitely many connected components of Y which converge to a point outside of Y. (3) Every homomorphism from π1(ℍ, o) to itself is conjugate to a homomorphism induced from a continuous map.
Original language | English |
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Pages (from-to) | 283-306 |
Number of pages | 24 |
Journal | Topology and its Applications |
Volume | 84 |
Issue number | 1-3 |
Publication status | Published - 1998 |
Keywords
- σ-word
- Free σ-product
- Fundamental group
- Hawaiian earring
- Plane
- Spatial homomorphism
- Standard homomorphism
ASJC Scopus subject areas
- Geometry and Topology