Download presentation

Presentation is loading. Please wait.

Published byRaul Syms Modified over 2 years ago

1
Obstructions to Compatible Extensions of Mappings Duke University Joint with John Harer Jose Perea

2
June 1994 Monday (05/26/2014)

3
June 1994 Incremental ‘s Monday (05/26/2014)

4
June 1994 Incremental ‘s Monday (05/26/2014)

5
June 1994 Incremental ‘s 2002 Topological Persistence Monday (05/26/2014)

6
June 1994 Incremental ‘s 2002 Topological Persistence 2005 Computing P.H. Monday (05/26/2014)

7
June 1994 Incremental ‘s 2002 Topological Persistence 2005 Computing P.H. 2008 Extended Persistence Monday (05/26/2014)

8
June 1994 Incremental ‘s 2002 Topological Persistence 2005 Computing P.H. 2008 Extended Persistence 2009 Zig-Zag Persistence … Monday (05/26/2014)

9
June 1994Monday (05/26/2014) Incremental ‘s 2002 Topological Persistence 2005 Computing P.H. 2008 Extended Persistence 2009 Zig-Zag Persistence

11
What have we learned? Study the whole multi-scale object at once Is not directionality, but compatible choices … …

12
For Point-cloud data: 1.Encode multi-scale information in a filtration-like object 2.Make compatible choices across scales 3.Rank significance of such choices

13
To leverage the power of the relative-lifting paradigm and the language of obstruction theory The Goal:

14
To leverage the power of the relative-lifting paradigm and the language of obstruction theory The Goal: For data analysis!

15
Why do we care?

16
Useful concepts/invariants can be interpreted this way: 1.The retraction problem: 2.Extending sections: 3.Characteristic classes.

17
Back to Point-clouds: Model fitting

18
Example (model fitting): (3-circle model) (Klein bottle model) Mumford Data

19
Model fitting Only birth-like events

20
Local to global Example: Compatible extensions of sections

21
Local to global Only death-like events

22
Local to global Model fitting

23
Combine the two: The compatible-extension problem

24
How do we set it up?

25
Definition : The diagram Extends compatibly, if there exist extensions of the so that.

26
For instance :

27
Let be the tangent bundle over, and fix classifying maps If then, where Thus, Extend separately but not compatibly

28
Let be the tangent bundle over, and fix classifying maps If then, where Thus, Extend separately but not compatibly

29
Let be the tangent bundle over, and fix classifying maps If then, where Thus, Extend separately but not compatibly

30
Let be the tangent bundle over, and fix classifying maps If then, where Thus, Extend separately but not compatibly

31
Observation: Relative lifting problem up to homotopy rel Compatible extension problem

32
How do we solve it?

33
Solving the classic extension problem: The set-up Assume Want

34
Solving the classic extension problem: The set-up Assume Want

35
Solving the classic extension problem: The set-up Assume Want

36
Solving the classic extension problem: Assume Want The obstruction cocycle

37
is a cocycle, and if and only if extends. Moreover, if for some then there exists a map so that on, and Theorem

38
is a cocycle, and if and only if extends. Moreover, if for some then there exists a map so that on, and Theorem

39
Solving the compatible extension problem: The set-up Assume

42
Let for some. Then is a cocycle, which is zero if and only if Theorem I (Perea, Harer)

43
Theorem II (Perea, Harer) Let. If for, then and extend compatibly.

44
The upshot: Once we fix so that, then parametrizes the redefinitions of that extend. Moreover, if a pair, satisfies then the redefinitions of and via and, extend compatibly.

45
The upshot: Once we fix so that, then parametrizes the redefinitions of that extend. Moreover, if a pair, satisfies then the redefinitions of and via and, extend compatibly.

46
Putting everything together

48
… … … … …

49
Example

56
Can we actually compute this thing?

58
* Some times

60
Coming soon: Applications to database consistency Topological model fitting Bargaining/consensus in social networks

61
Thanks!!

Similar presentations

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google