Desuspension
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In topology, a field within mathematics, desuspension is an operation inverse to suspension.[1]
Definition
In general, given an n-dimensional space , the suspension has dimension n + 1. Thus, the operation of suspension creates a way of moving up in dimension. In the 1950s, to define a way of moving down, mathematicians introduced an inverse operation , called desuspension.[2] Therefore, given an n-dimensional space , the desuspension has dimension n – 1.
Reasons
The reasons to introduce desuspension:
- Desuspension makes the category of spaces a triangulated category.
- If arbitrary coproducts were allowed, desuspension would result in all cohomology functors being representable.