1. Introduction
We can fix some Riemannian metric g on a manifold Mn of dimension n which defines the length of arc of a piecewise smooth curve and the continuous function
of the distance between two points
. The topology defined by the function of distance (metric)
is the same as the topology of the manifold Mn [1].
In Section 1, using a smooth triangulation considered in the main theorem and a Riemannian metric we construct an algorithm of extension of coordinate neighborhood. With the help of this algorithm we get that every compact, connected, closed manifold Mn of dimension n having the triangulation above can be represented as a union of a n-dimensional cell Cn and a connected union
of some finite number of simplexes of the triangulation having dimension less or equal
. A sufficiently small closed neighborhood of
is called a geometric black hole [2]. Simplexes with boundaries can be retracted i.e. a decomposition
can be obtained where
contains less simplexes than
does.
In Section 2, we consider the proof of the main theorem consisting of the realization of several algorithms. Using the method of mathematical induction and the algorithms we retract all the simplexes from
to a point x0, therefore a decomposition
is obtained and Mn is homeomorphic to the sphere
.
2. On Algorithm of Extension of Coordinate Neighborhood
1) Let Mn be a connected, compact, closed and smooth manifold of dimension n and Cn be a cell (coordinate neighborhood) on Mn. A standard simplex ∆n of dimension n is the set of points
defined by conditions

We consider the interval of a straight line connected the center of some face of ∆n and the vertex which is opposite to this face. It is clear that the center of ∆n belongs to the interval. We can decompose ∆n as a set of intervals which are parallel to that mentioned above. If the center of ∆n is connected by intervals with points of some face of ∆n then a subsimplex of ∆n is obtained. All the faces of ∆n considered, ∆n is seen as a set of all such subsimplexes. Let
be some open neighborhood of ∆n in Rn. A diffeomorphism
is called a singular nsimplex on the manifold Mn. Faces, edges, the center, vertexes of the simplex
are defined as the images of those of ∆n with respect to
.
The manifold Mn is triangulable [3]. It means that for any
such a finite set
of diffeomorphisms
is defined that
a) Mn is a disjunct union of images
;
b) if
then
for every i where
is the linear mapping transferring the vertexes
of the simplex
in the vertexes
of the simplex
.
We suppose that there exists a smooth finite triangulation on Mn which is coordinated with the smoothness structure of Mn and fix the triangulation. Such triangulations exist for manifolds of dimension 2 or 3.
2) Let
be some simplex of the fixed triangulation of the manifold Mn. We paint the inner part
of the simplex
white and the boundary
of
black. There exist coordinates on
given by diffeomorphism
. A subsimplex
is defined by a black face
and the center
of
. We connect
with the center
of the face
and decompose the subsimplex
as a set of intervals which are parallel to the interval
. The face
is a face of some simplex
that has not been painted. We draw an interval between
and the vertex
of the subsimplex
which is opposite to the face
then we decompose
as a set of intervals which are parallel to the interval
. The set
is a union of such broken lines every one from which consists of two intervals where the endpoint of the first interval coincides with the beginning of the second interval (in the face
) the first interval belongs to
and the second interval belongs to
. We construct a homeomorphism (extension)
:
. Let us consider a point
and let x belong to a broken line consisting of two intervals the first interval is of a length of
and the second interval is of a length of
and let x be at a distance of s from the beginning of the first interval. Then we suppose that
belongs to the same broken line at a distance of
from the beginning of the first interval. It is clear that
is a homeomorphism giving coordinates on
. We paint points of
white. Assuming the coordinates of points of white initial faces of subsimplex
to be fixed we obtain correctly introduced coordinates on
. The set
is called a canonical polyhedron. We paint faces of the boundary
black.
We describe the contents of the successive step of the algorithm of extension of coordinate neighborhood. Let us have a canonical polyhedron
with white inner points (they have introduced white coordinates) and the black boundary
. We look for such an n-simplex in
, let it be
that has such a black face, let it be
that is simultaneously a face of some n-simplex, let it be
, inner points of which are not painted. Then we apply the procedure described above to the pair
,
. As a result we have a polyhedron
with one simplex more than
has. Points of
are painted white and the boundary
is painted black. The process is finished in the case when all the black faces of the last polyhedron border on the set of white points (the cell) from two sides.
After that all the points of the manifold
are painted in black or white, otherwise we would have that
(the points of
would be painted and those of
would be not) with
and
being unconnected, which would contradict of connectivity of
.
Thus, we have proved the following.
Theorem 1. Let
be a connected, compact, closed, smooth manifold of dimension n. Then
,
, where
is an п-dimensional cell and
is a union of some finite number of
-simplexes of the triangulation.
3) We consider the initial simplex
of the triangulation and its center
. Drawing intervals between the point
and points of all the faces of
we obtain a decomposition of
as a set of the intervals. In 2) the homeomorphism
:
was constructed and
evidently maps every interval above on a piecewise smooth broken line
in Cn. We denote
.
is a connected and simply connected manifold if
is that. Let
, we define a homotopy
in the following way
a)
for every point
;
b) if a point x belongs to the broken line
in
and the distance between x and its limit point
is
then
is on the same broken line
at a distance of
from the point z.
It is clear that
,
and we have obtained the following.
Theorem 2. The spaces
and
are homotopyequivalent, in particular, the groups of singular homologies
and
are isomorphic for every k.
Corollary 2.1. The space
is connected and if Mn is simply connected then
is simply connected too.
Remark 1. The white coordinates are extended from the simplex
in the simplex
through the face
hence
has also the white coordinates. On the other hand there exist two linear structures (intervals, the center etc.) on
induced from
and
respectively. Further, we set that the linear structure of
is the structure induced from
.
Remark 2. In the process of getting of
in 2) we can construct a maximal tree L connecting by intervals all the centers of the n-simplexes of the triangulation via the centers of some white faces.
Conversely, if we have such a maximal tree L connecting by intervals all the centers of the n-simplexes of the triangulation via the centers of some faces (any from two possible centers of a face can be chosen) then we can extend white coordinates from any simplex
on the maximal cell Cn as it was shown in 2). Thus, the maximal tree L defines the maximal cell C3 and white faces.
4) Definition 1.
a) A simplex
is called free if it has at least one free face
i.e. such a face that it is not a face of any other k-simplex from
.
b) An edge
is called semi-isolated if it is not an edge of any simplex from
. A semi-isolated edge
is called isolated if it is free.
Let us have a free simplex
with some free face
. We consider such a polyhedron
that
is the set of all n-simplexes having common point with
.
Proposition 3. We can redistribute coordinates of white points of the polyhedron
(retract the free simplex
) i.e. construct the corresponding mapping
in such a way that the following conditions are fulfilled:
a) all the points of
are painted white i.e. have new white coordinatesb) white coordinates of points of boundary faces of the polyhedron
are not changed.
Proof. a) We consider the unit disk D2 having the center in the origin
of the coordinate system
of
and the radius
.

We define a mapping
by the following way:
• 
• for any chord
which is parallel to
, 
It is clear that
maps
onto
and
on the boundary circle of
.
b) We consider the unit disk
having the center in the origin
of the coordinate system
and the semidisk
,
,
. By inductive hypothesis we assume that such a mapping
has been constructed that
maps
onto
and
on the boundary of
.
Further, we consider the unit disk
in the coordinate system
, the semidisk
,
and the family of disks
,
,
. We denote
By inductive hypothesis there exists such the family of mappings
that every
maps
onto
and
on the boundary of
. Union of all
gives the mapping
,
maps
onto
and
on the boundary of
.
Thus, the mapping
is constructed for any
by the method of mathematical induction.
c) It is clear that there exists such a homeomorphism
that
and
. We define the mapping
then
is a required homeomorphism introducing new white coordinates in
.
QED.
Remark 3. In is clear that the rebuilt complex
is connected and simply connected because of a homotopy-equivalence.
5) We assume that in the process of painting free simplexes white by the Proposition 3 we get a representation
, where K1 is the connected union of black edges of the triangulation. Since the process of painting free simplexes white does not influence simply connectivity of a space that has been obtained every step then K1 is a tree if the complex
is simply connected. Painting isolated edges of K1 white by the Proposition 3 we have got unique black point x0 as result. Thus, we obtain a representation
, where
is an open geodesic ball with the center in x0 and of a radius
. The manifold Mn is homeomorfic to the sphere Sn by the following lemma 4.
Lemma 4 [1]. If a topological manifold Mn is a union of two n-dimensional cells then Mn is homeomorfic to the sphere Sn.
3. Proof of the Main Theorem
The proof has a combinatorial nature and assumes the realization of a number of algorithms. We consider that step by step. The initial complex
is assumed to be connected, simply connected and without free simplexes.
1) Proposition 5 (opening an input). Let
be some n–simplex of the triangulation having a black face
. Then
can be repainted white to get a new decomposition
, where
is a new connected and simply connected complex.
Proof. The face
is the common face of n-simplexes
and
. We cansel the white painting of points of
and paint the n-simplexe
black. Repainting of
black brings to a gap of the maximal tree L (see the Remark 2) on n subtrees
or less where the center of
belongs to
. Further, we extend white coordinates from
into
through the face
as it was shown in 2), 1 and connect the centers of
,
,
by intervals. Those centers belong to the subtree
. Other faces of
are black and they are simultaneously some faces of other n-simplexes.
We consider the following cases.
a)
or we have no a gap. The black faces of
remain black.
b) We have got k subtrees
where the subtrees
define cells called dead ends. We repaint the closures of the dead ends black. Further, we are looking for a black face of
which is simultaneously a face of other n-simplex with the center from
. This face remains black. For every subtree
we consider a n-simplex with the center from
that has a common black face
with
. We extend white coordinates from
through
along the subtree
as it was shown in 2), 1 and repaint inner points of this face and points of the corresponding dead end white. Further, we connect by intervals the centers of
with the centers of
and the other simplex connecting
and
.
After repainting all the dead ends white we obtain a new maximal tree L defining a new maximal cell
. Retracting all the free simplexes by the Proposition 3 a new rebuilt complex
is obtained which is connected and simply connected because of homotopyequivalence.
QED.
Remark 4. A broken line has been obtained in the proof above which connects by intervals the centers of
,
,
. This broken line is a part of the subtree
of the maximal tree L. Let n-simplexes
and
have a common face
having the white inter part and
has no common points with the maximal tree
. Then we can connect the centers of
,
,
by the broken line by the method considered in the proof above.
2) We assume the following inductive hypothesis:
The generalized Poincare conjecture (the main theorem) can be proved by the method considered in [4] for dimension n–1 i.e. the representation
can be obtained by the algorithm from 2), 1 and by the Propositions 3, 4, 5.
It is obvious for
(see 5), 1) It is proved for
in [4].
We choose a small ball
with the center in a vertex x0 which is diffeomorphic to a small ball in
and call a trace of k-simplex
with a vertex in x0 its intersection
with the sphere
(smooth manifold) which is the boundary of
. The sphere
is supposed to be transversal to all the k-simplexes
with the vertex x0. Such a sphere
exists because of the smoothness of the triangulation of Mn [5,6]. All other vertexes of the triangulation are supposed to be out of
. The ball
can be chosen in such a vay that every edge with the endpoint x0 has only one point of the intersection with
and every k-simplex
with the vertex x0 has only one connected component
of
. Let
be the set of black k-simplexes with x0 as their vertex and
.
There exists one to one correspondence between the set of simplexes having a vertex (endpoint) x0 and the set of their traces on
therefore all steps of the algorithm below bring to the corresponding steps on the sphere
and the converse is true. In particular, a process of the construction of a maximal tree
on the sphere
(see the Remark 2) brings to the construction of a tree L1 connecting by intervals all the centers of the n-simplexes with x0 as their vertex via the centers of some white their faces. Every such the face has x0 as its vertex.
Proposition 6. The complex
can be rebuilt in such a vay that
contains only one 1-simplex
.
Proof. We consider the smooth triangulation of
induced by all the simplexes with the vertex
and apply to this triangulation the algorithm from 2), 1 taking any
-simplex
as initial one where
is the trace of
with a vertex
. Let
be the trace on
of
with a vertex x0 where
has a common face with
. We repaint
black and apply to it the proposition 5 (the remark 4) obtaining the canonical polyhedron
on
. Further, we iterate the algorithm. Every step of the algorithm on
implies the transformation of
and
by the proposition 5 (the remark 4). The maximal tree
on
and the corresponding subtree
have been constructed in the end. Further, free black simplexes on
and the corresponding free simplexes from
can be annihilated by the propositions 3, 4, 5. By the inductive hypothesis only one black point remains on
in the end. This point is the trace of an edge
which is isolated.
QED.
Remark 5. It is clear that if we paint black one inner vertex in the canonical polyhedron then we get two black points on
in the end of the algorithm.
3) We consider a small ball
with the center
and the boundary
which is similar to
. The centers of all the n-simplexes having
as their edge belong to the subtree L1 and the union of all the traces of this n-simplexes on
forms the canonical polyhedron on
having one black inner vertex (the trace of isolated edge
). We apply the Proposition 6 (the Remark 5) to the
and
. As a result
consists of two semi-isolated edges
and
.
Further, we iterate the process getting a broken line
and for
consists of two black semi-isolated edges
and
. We remark that the process of the annihilation of black simplexes in
cannot bring to an appearance of a black simplex having a generic point with
. Really, otherwise such a black simplex gives an opportunity to connect the endpoints
and
of the semi-isolated edge
by a black curve which is different from
. As a result a black loop with the semi-isolated edge
as its part has been obtained and the loop is not contractible that is a contradiction to the simply connectivity of
.
The complex
is connected therefore the broken line
contains all the possible black vertexes from
at some step of the algorithm i.e. we come to 5, 1.
By the method of mathematical induction the main theorem is true for every 