Proof:

If $ k = 0$ then $ K$ is a point and $ S^n - K$ is homeomorphic to $ \mathbb{R}^n$ and the result is true in this case. The proof now proceeds by induction on $ k$. Assume that the result has been proved for $ 0 \leq k \leq m-1$ and let $ h:K\longrightarrow I^m$ be a homeomorphism. Define the halves $ I^{+}$ and $ I^{-}$ as

$\displaystyle I^{+} = \{(x_1, x_2,\dots, x_m) \in I^m\;/\; x_n \geq 1/2\}, \quad
I^{-} = \{(x_1, x_2,\dots, x_m) \in I^m\;/\; x_n \leq 1/2\}
$

and note that $ I^{+}\cap I^{-}$ is homeomorphic to the cube $ I^{m-1}$. We construct the sets $ K^{+} = h^{-1}(I^{+})$ and $ K^{-} = h^{-1}(I^{-})$, and use the Mayer Vietoris sequence to the following open cover of $ S^n - (K^{+}\cap K^{-1})$:

$\displaystyle \{S^n - K^{+},\; S^n - K^{-}\}.
$

Since $ K^{+}\cap K^{-}$ is homeomorphic to $ I^{m-1}$, by induction hypothesis the end terms of the portion

$\displaystyle \begin{CD}
\phantom{X}H_{j+1}(S^n-K^{+}\cap K^{-})@> >> H_j(S^n -...
...S^n-K^{-})@> >> \phantom{X}\\
@> q_j >> H_j(S^n - K^{+}\cap K^{-})\\
\end{CD}$

are zero if $ j > 0$ whereas the left most group is zero if $ j = 0$. In any case $ (\kappa^{\prime}, -\kappa^{\prime\prime})$ is injective. Assume that for some $ j > 0$, $ H_j(S^n - K) \neq 0$. We choose $ \zeta \in H_j(S^n - K)$, $ \zeta \neq 0$ and it follows $ \kappa^{\prime}(\zeta) \neq 0$ or $ \kappa^{\prime\prime}(\zeta) \neq 0$. Let us assume that $ \kappa^{\prime}(\zeta) \neq 0$. Since $ K^{+}$ is homeomorphic to $ I^m$, the process can be repeated subdividing $ K^{+}$ into two pieces whose intersection is homeomorphic to $ I^{m-1}$. Thus we construct a nested sequence of subsets

$\displaystyle K = K_1 \supseteq K_2 \supseteq K_3 \supseteq \ldots
$

such that for each $ p$, the map $ \kappa_p:H_j(S^n - K)\longrightarrow H_j(S^n - K_p)$ induced by inclusion, maps $ \zeta$ to a non zero element. Composing with $ f_p:H_j(S^n-K_p)\longrightarrow \varinjlim H_j(S^n - K_p)$ one checks that for $ p, q \in \mathbb{N}$,

$\displaystyle f_p\circ \kappa_p = f_q\circ \kappa_q,
$

thereby providing a map

$\displaystyle f:H_j(S^n - K)\longrightarrow \varinjlim H_j(S^n - K_p).
$

Since the intersection $ \bigcap K_i$ is homeomorphic to $ I^{m-1}$, by induction hypothesis, $ \varinjlim H_j(S^n - K_p) = \{0\}$. Hence $ f_p(\kappa_p(\zeta)) = 0$ for every $ p$ and hence by theorem (40.2) (ii), for some $ q \in \mathbb{N}$, $ \kappa_q(\zeta) = 0$ which is a contradiction.

Turning to the case $ j = 0$, assume that rank of $ H_0(S^n - K)$ is atleast two. If we select points $ x$ and $ y$ lying in distinct path components of $ S^n - K$, the cycle $ \zeta = x - y$ in $ S^n - K$ is not a boundary. As before we construct a nested sequence of compact sets $ \{K_p\}$ with $ \kappa_p(\zeta) \neq 0$ for each $ p \in \mathbb{N}$. But since $ S^n - \bigcap K_p$ has only one path component, $ \iota_p\circ \kappa_p(\zeta)$ is a boundary where $ \iota_p$ is the map induced by the inclusion $ S^n - K_p \longrightarrow S^n - \bigcap K_p$ whence

$\displaystyle f_p(\kappa_p(\zeta)) = 0
$

by (41.3). This in turn forces $ \kappa_p(\zeta) = 0$ by theorem (40.2) (ii) and we have a contradiction.
nisha 2012-03-20