ADJ.
direct, infinite, many
VERB + COUNTABLY
called
COUNTABLY + NOUN
summands
ADV.
only
adv
In a countable manner; in a way that can be counted.
In a way that can be put into one-to-one correspondence with the natural numbers or any subset thereof.
The module has only countably many direct summands up to isomorphism.
A set with the cardinality of the natural numbers is called "countably infinite".