Baer-Specker relations
embedding of A3 into S3
embedding of integers into rational numbers
example of a non-strong extremal monomorphism
handle of the universal fork
identity map of a group
identity map of a set
inclusion of positive numbers
map from the empty set
map into the singleton set
multiplication by 2
presentation of the walking idempotent
reduction modulo p
universal morphism
universal split epimorphism