It is shown that for every two countable ordinals $\alpha $ and $\beta $ with $\alpha > \beta $ there exist $\lambda $-dendroids $X$ and $Y$ whose depths are $\alpha $ and $\beta $ respectively, and a monotone retraction from $X$ onto $Y$. Moreover, the continua $X$ and $Y$ can be either both arclike or both fans.
@article{107501, author = {Janusz Jerzy Charatonik and Panayotis Spyrou}, title = {Monotone retractions and depth of continua}, journal = {Archivum Mathematicum}, volume = {030}, year = {1994}, pages = {131-137}, zbl = {0817.54011}, mrnumber = {1292564}, language = {en}, url = {http://dml.mathdoc.fr/item/107501} }
Charatonik, Janusz Jerzy; Spyrou, Panayotis. Monotone retractions and depth of continua. Archivum Mathematicum, Tome 030 (1994) pp. 131-137. http://gdmltest.u-ga.fr/item/107501/
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