##  [Obstruction Class](/obstruction-class) 

  ##  [Obstruction Class](https://puremath.quantumdictionary.io/obstruction-class-0) 

  

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**Pure Mathematics Dictionary**

 







 

 

 

 



 

 

 

 

Definition

A cohomology class or analogous invariant that measures the obstruction to performing a desired construction or extension in an algebraic (or homotopical) context; typically it vanishes if and only if the construction can be carried out at that stage.