@article {1804.03701, archivePrefix = {arXiv}, eprint = {1804.03701}, primaryClass = {math.CO}, author = {Jonah Blasiak and Jennifer Morse and Anna Pun and Daniel Summers}, title = {Catalan functions and $k$-Schur positivity}, year = {2018}, url = {http://arxiv.org/abs/1804.03701} }