Jesús Ferrer, Enrique Llorens-Fuster. A Short Proof that Some Mappings of the Unit Ball of ℓ2 Are Never Nonexpansive. The American Mathematical Monthly, 127(4):354-358, 2020. [doi]
@article{FerrerL20,
title = {A Short Proof that Some Mappings of the Unit Ball of ℓ2 Are Never Nonexpansive},
author = {Jesús Ferrer and Enrique Llorens-Fuster},
year = {2020},
doi = {10.1080/00029890.2020.1704168},
url = {https://doi.org/10.1080/00029890.2020.1704168},
researchr = {https://researchr.org/publication/FerrerL20},
cites = {0},
citedby = {0},
journal = {The American Mathematical Monthly},
volume = {127},
number = {4},
pages = {354-358},
}