![]() ![]() ![]() ![]() |
![]() ![]() ![]() ![]() |
A species of structures is a rule which
The functions should further satisfy the following functorial properties:
An element
is called an
-structure on
(or a structure of species
on
). The function
is called the transport of
-structures along
.
References
Bergeron, F.; Labelle, G.; and Leroux, P. Combinatorial Species and Tree-Like Structures.
Cambridge, England: Cambridge University Press, p. 5, 1998.