# Weierstrass Thm: Continuous Fn Attaining Extrema on Compact Domain $u:\mathbb{R^L}\rightarrow\mathbb{R}$

This is just semantics, but MWG doesn't use the Weierstrass Theorem in its Math Appendix when using the fact that a continuous function always has a max value on any compact set.

Some books appeal directly to the Weierstrass Theorm.

Is there a right or wrong answer to this? Or is it more just, like I said, semantics?

• Excuse me but what is your question? – Giskard Jun 29 '16 at 7:12
• The Weierstrass Extreme Value Theorem guarantees this. However, it's used so frequently that economists take it for granted or omit it in graduate courses and research papers sometimes. MWG is a maturity book. Part of mathematical maturity is being able to fill in the details for a proof. – ml0105 Jun 29 '16 at 19:15
• @ml0105, thank you for the comment, that was exactly what I was looking for. Somethings are obvious to some and not to others haha! – Frank Swanton Jul 1 '16 at 13:02
• @ml0105, if you put that as answer, I will select it. This post will be useful to those who might been confused like me – Frank Swanton Jul 1 '16 at 13:04
• I've made my comment an answer. :-) – ml0105 Jul 1 '16 at 14:56