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Cubical sets have a directed homology, studied in a previous paper and consisting of preordered abelian groups, with a positive cone generated by the structural cubes. By this additional information, cubical sets can provide a sort of `noncommutative topology', agreeing with some results of noncommutative geometry but lacking the metric aspects of C* -algebras. Here, we make such similarity stricter by introducing normed cubical sets and their normed directed homology, formed of normed preordered abelian groups. The normed cubical sets NC_\theta associated with `irrational' rotations have thus the same classification up to isomorphism as the well-known irrational rotation C* -algebras A_\theta.
@article{TAC_2004_13_a6, author = {Marco Grandis}, title = {Normed combinatorial homology and noncommutative tori}, journal = {Theory and applications of categories}, pages = {114--128}, publisher = {mathdoc}, volume = {13}, year = {2004}, language = {en}, url = {http://geodesic.mathdoc.fr/item/TAC_2004_13_a6/} }
Marco Grandis. Normed combinatorial homology and noncommutative tori. Theory and applications of categories, The Carboni Festschrift, Tome 13 (2004), pp. 114-128. http://geodesic.mathdoc.fr/item/TAC_2004_13_a6/