Hacker Newsnew | past | comments | ask | show | jobs | submitlogin

I do not understand your question: a set is infinite if and only if there is a bijection between it and one of its strict subsets.

As formal as it gets.

Edit: (not intending to be harsh, just that I probably lack some context to properly understand what you are asking).



Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: