Theorem 6.11.
Assuming that:
C
a
category
Then
the following are equivalent:
(i)
C
is
equivalent
to a finitary algebraic
category
in the sense of Example
5.14
(a). (Recall that these
categories
are those whose objects are sets with finitary operations satisfying some equations, and morphisms are homomorphisms between them.)
(ii)
C
is
equivalent
to the
category
of
S
e
t
-
models
of a
Lawvere theory
.
(iii)
C
≃
S
e
t
𝕋
for a finitary
monad
𝕋
on
S
e
t
.