983 research outputs found
Stable comparison of multidimensional persistent homology groups with torsion
The present lack of a stable method to compare persistent homology groups with torsion is a relevant problem in current research about Persistent Homology and its applications in Pattern Recognition. In this paper we introduce a pseudo-distance d_T that represents a possible solution to this problem. Indeed, d_T is a pseudo-distance between multidimensional persistent homology groups with coefficients in an Abelian group, hence possibly having torsion. Our main theorem proves the stability of the new pseudo-distance with respect to the change of the filtering function, expressed both with respect to the max-norm and to the natural pseudo-distance between topological spaces endowed with vector-valued filtering functions. Furthermore, we prove a result showing the relationship between d_T and the matching distance in the 1-dimensional case, when the homology coefficients are taken in a field and hence the comparison can be made
Stable comparison of multidimensional persistent homology groups with torsion
The present lack of a stable method to compare persistent homology groups
with torsion is a relevant problem in current research about Persistent
Homology and its applications in Pattern Recognition. In this paper we
introduce a pseudo-distance d_T that represents a possible solution to this
problem. Indeed, d_T is a pseudo-distance between multidimensional persistent
homology groups with coefficients in an Abelian group, hence possibly having
torsion. Our main theorem proves the stability of the new pseudo-distance with
respect to the change of the filtering function, expressed both with respect to
the max-norm and to the natural pseudo-distance between topological spaces
endowed with vector-valued filtering functions. Furthermore, we prove a result
showing the relationship between d_T and the matching distance in the
1-dimensional case, when the homology coefficients are taken in a field and
hence the comparison can be made.Comment: 10 pages, 3 figure
Multidimensional persistent homology is stable
Multidimensional persistence studies topological features of shapes by
analyzing the lower level sets of vector-valued functions. The rank invariant
completely determines the multidimensional analogue of persistent homology
groups. We prove that multidimensional rank invariants are stable with respect
to function perturbations. More precisely, we construct a distance between rank
invariants such that small changes of the function imply only small changes of
the rank invariant. This result can be obtained by assuming the function to be
just continuous. Multidimensional stability opens the way to a stable shape
comparison methodology based on multidimensional persistence.Comment: 14 pages, 3 figure
Invariance properties of the multidimensional matching distance in Persistent Topology and Homology
Persistent Topology studies topological features of shapes by analyzing the
lower level sets of suitable functions, called filtering functions, and
encoding the arising information in a parameterized version of the Betti
numbers, i.e. the ranks of persistent homology groups. Initially introduced by
considering real-valued filtering functions, Persistent Topology has been
subsequently generalized to a multidimensional setting, i.e. to the case of
-valued filtering functions, leading to studying the ranks of
multidimensional homology groups. In particular, a multidimensional matching
distance has been defined, in order to compare these ranks. The definition of
the multidimensional matching distance is based on foliating the domain of the
ranks of multidimensional homology groups by a collection of half-planes, and
hence it formally depends on a subset of inducing a
parameterization of these half-planes. It happens that it is possible to choose
this subset in an infinite number of different ways. In this paper we show that
the multidimensional matching distance is actually invariant with respect to
such a choice.Comment: 14 pages, 2 figure
Persistence of Zero Sets
We study robust properties of zero sets of continuous maps
. Formally, we analyze the family
of all zero sets of all continuous maps
closer to than in the max-norm. The fundamental geometric property
of is that all its zero sets lie outside of .
We claim that once the space is fixed, is \emph{fully} determined
by an element of a so-called cohomotopy group which---by a recent result---is
computable whenever the dimension of is at most . More explicitly,
the element is a homotopy class of a map from or into a sphere.
By considering all simultaneously, the pointed cohomotopy groups form a
persistence module---a structure leading to the persistence diagrams as in the
case of \emph{persistent homology} or \emph{well groups}. Eventually, we get a
descriptor of persistent robust properties of zero sets that has better
descriptive power (Theorem A) and better computability status (Theorem B) than
the established well diagrams. Moreover, if we endow every point of each zero
set with gradients of the perturbation, the robust description of the zero sets
by elements of cohomotopy groups is in some sense the best possible (Theorem
C)
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