Real Zero is Less than Real One

Theorem

The real number $0$ is less than the real number $1$:

$0 < 1$


Proof

\(\ds 1 \times 1\) \(>\) \(\ds 0\) Square of Non-Zero Real Number is Strictly Positive
\(\ds \leadsto \ \ \) \(\ds 1\) \(>\) \(\ds 0\) Real Number Axiom $\R \text M3$: Identity Element for Multiplication
\(\ds \leadsto \ \ \) \(\ds 0\) \(<\) \(\ds 1\) Definition of Dual Ordering

$\blacksquare$


Sources

  • 2000: James R. Munkres: Topology (2nd ed.) ... (previous) ... (next): $1$: Set Theory and Logic: $\S 4$: The Integers and the Real Numbers: Exercise $2 \ \text{(g)}$