Corrigendum: “On the computing powers of L-reductions of insertion languages” (Theoretical Computer Science (2021) 862 (224–235), (S030439752030668X), (10.1016/j.tcs.2020.11.029))

The authors regret that the proof for Theorem 4 in the article “On the computing powers of [Formula presented]-reductions of insertion languages” was incomplete, which was pointed out by Kaoru Fujioka, Fukuoka Women's University, Japan. The proof needs some supplementary corrections for constructing the insertion system γ and [Formula presented]. Specifically, in the proof (on page 231), 1. line 4: Correct as [Formula presented], we construct the following rules: [Formula presented] 3.