In this case , if a proof uses this statement , researchers will often look for a new proof that does not require the hypothesis The one major exception to this in practice is the axiom of choice -- unless studying this axiom in particular , the majority of researchers do not usually worry whether a result requires the axiom of choice . In this case , if a proof uses this statement , researchers will often look for a new proof that does n't require the hypothesis ( in the same way that it is desirable that statements in Euclidean geometry be proved using only the axioms of neutral geometry , i.e. no parallel postulate . ) The one major exception to this in practice is the axiom of choiceâ '' unless studying this axiom in particular , the majority of researchers do not usually worry whether a result requires the axiom of choice .