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						double groupoid with connection
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						(Definition)
						
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 In the setting of a geometrically defined double groupoid with connection, as in [2], (resp. [3]), there is an appropriate notion of geometrically thin square. It was proven in [2], (theorem 5.2 (resp. [3], proposition 4)), that in the cases there specified geometrically and algebraically thin squares coincide. 
We briefly recall here the related concepts involved: 
Definition 0.2   A  square 
  in a  topological space    is  thin if there is a factorisation of   ,
 
where    is a  tree and    is piecewise linear (PWL, as defined next) on the  boundary 
  of   .  
Definition 0.3   A  tree, is defined here as the underlying space    of a finite   -connected   -dimensional simplicial complex    boundary 
   of   .  
- 1
 
- Ronald Brown: Topology and Groupoids, BookSurge LLC (2006).
 
- 2
 
- Brown, R., and Hardy, J.P.L.:1976, Topological groupoids I: universal constructions, Math. Nachr., 71: 273-286.
 
- 3
 
- Brown, R., Hardie, K., Kamps, H. and T. Porter: 2002, The homotopy double groupoid of a Hausdorff space., Theory and pplications of Categories 10, 71-93.
 
- 4
 
- Ronald Brown R, P.J. Higgins, and R. Sivera.: Non-Abelian algebraic topology,(in preparation),(2008). (available here as PDF) , see also other available, relevant papers at this website.
 
- 5
 
- R. Brown and J.-L. Loday: Homotopical excision, and Hurewicz theorems, for 
 -cubes of spaces, Proc. London Math. Soc., 54:(3), 176-192,(1987). 
- 6
 
- R. Brown and J.-L. Loday: Van Kampen Theorems for diagrams of spaces, Topology, 26: 311-337 (1987).
 
- 7
 
- R. Brown and G. H. Mosa: Double algebroids and crossed modules of algebroids, University of Wales-Bangor, Maths (Preprint), 1986.
 
- 8
 
- R. Brown and C.B. Spencer: Double groupoids and crossed modules, Cahiers Top. Géom. Diff., 17 (1976), 343-362.
 
 
  
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  "double groupoid with connection" is owned by bci1.
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		See Also: index of algebraic topology
  
 
Cross-references: boundary, tree, topological, concepts, simplicial, piecewise linear, simplicial complexes, thin squares, proposition, theorem, square, geometrically defined double groupoid with connection 
 
This is version 1 of double groupoid with connection, born on 2009-01-31. 
Object id is 451, canonical name is DoubleGroupoidWithConnection. 
Accessed 1025 times total. 
 Classification: 
	
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