# Should I correct my own mistakes in my question, after the answer has been given?

I'm referring specifically to (but not restricting my question to) this question that I recently posted:

Are there as many real numbers as there are imaginary numbers?

A couple of things that I've stated as true in the question are actually false (due to my mistunderstanding); the first being that infinite sets always have same cardinality (false) and the second being that there is no bijection between $\mathbb{R}$ and $\mathbb{I}$ (false, as Asaf Karagila has shown).

My question is:

Now that I've seen the error of my ways, should I leave the question and its errors intact (in which case I might be spreading mathematical falseness) or should I correct the question (in which case the answer and the question might not make sense anymore)?

• If possible, <strike>strike out the mistakes</strike> using the <strike>...</strike> construct. Edit the question and add a note apologize for the confusion and state clearly what has been changed. Jul 10 '14 at 16:53
• @achillehui Users should not need to apologize for making mathematical mistakes.
– user147263
Jul 10 '14 at 16:56
• @Thisismuchhealthier. It is not needed but this is basic human courtesy. If you make a mistake, admit it and move on. Jul 10 '14 at 17:46

Usually this is not necessary: plenty of statements made in questions turn out to be incorrect, and as long as the answers clearly say so, there's no problem.

But if you'd like, you can add a footnote to the post, like this:

On the other hand, there's no bijection[1] .....

[1] Added later: this was shown to be false by the answerers

Here I am using HTML tags to create a pseudo-footnote: the source code

 On the other hand, there's no bijection<sup>[1]</sup> .....

---
<sup>[1] Added later: this was shown to be false by the answerers</sup>