Metric Small Cancellation Conditions
Let 0 < λ < 1. Presentation (∗) as above is said to satisfy the C'(λ) small cancellation condition if whenever u is a piece with respect to (∗) and u is a subword of some r ∈ R, then |u| < λ|r|. Here |v| is the length of a word v.
The condition C'(λ) is sometimes called a metric small cancellation condition.