From a5041f349a38afc6a9fe6ea9d30f8df434e31790 Mon Sep 17 00:00:00 2001 From: eggy Date: Mon, 13 Feb 2023 16:25:29 -0500 Subject: [PATCH] ece108: countably infinite fns are bijective --- docs/1b/ece108.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/docs/1b/ece108.md b/docs/1b/ece108.md index e960436..40ea36d 100644 --- a/docs/1b/ece108.md +++ b/docs/1b/ece108.md @@ -600,7 +600,7 @@ If $f: X\to Y$ and $g: Y\to Z$ are bijective: ## Cardinality !!! definition - - A **countably infinite** set is such that there exists a function that maps the set to the set of natural numbers. + - A **countably infinite** set is such that there exists a **bijective** function that maps the set to the set of natural numbers. - A **countable** set is a finite set or a countably infinite set. - An **uncountable** or **uncountably infinite** set is not countable.