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Exercise 1167Logic, sets and proofs › RelationsL1Added 3 Nov 2026

Total orders

#total order#comparability#real numbers

Statement

Show that (R,≤)(\mathbb{R},\le) is a total order.

Hint

Check reflexivity, antisymmetry, transitivity, totality.

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Solution

Reflexive. x≤xx\le x.

Antisymmetric. x≤yx\le y and y≤x⇒x=yy\le x\Rightarrow x=y.

Transitive. x≤y≤z⇒x≤zx\le y\le z\Rightarrow x\le z.

Total. For all x,yx,y, either x≤yx\le y or y≤xy\le x.

Conclusion. (R,≤)(\mathbb{R},\le) is a total order.