Every group is representable by all natural transformations of some set-functor.

@article{Barto2005,
author = {Barto, Libor, Zima, Petr},
journal = {Theory and Applications of Categories [electronic only]},
keywords = {set functor; automorphism group; endomorphism monoid},
language = {eng},
pages = {294-309},
publisher = {Mount Allison University, Department of Mathematics and Computer Science, Sackville},
title = {Every group is representable by all natural transformations of some set-functor.},
url = {http://eudml.org/doc/125324},
volume = {14},
year = {2005},
}

TY - JOUR
AU - Barto, Libor
AU - Zima, Petr
TI - Every group is representable by all natural transformations of some set-functor.
JO - Theory and Applications of Categories [electronic only]
PY - 2005
PB - Mount Allison University, Department of Mathematics and Computer Science, Sackville
VL - 14
SP - 294
EP - 309
LA - eng
KW - set functor; automorphism group; endomorphism monoid
UR - http://eudml.org/doc/125324
ER -