This is the question, and we're supposed to answer if it's true or false:(adsbygoogle = window.adsbygoogle || []).push({});

If A is a countably infinite set, and A is a proper subset of another set B,

then B is uncountable.

I thought this was false, because if A is infinite and countable, then B should also be infinite and countable in the same way A is if it's a proper subset of B. Could we list elements of A, then elements of B that are not contained in A?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: A simple question about counting and sets

**Physics Forums | Science Articles, Homework Help, Discussion**