Metamath Proof Explorer


Theorem n2dvds1

Description: 2 does not divide 1. That means 1 is odd. (Contributed by David A. Wheeler, 8-Dec-2018) (Proof shortened by Steven Nguyen, 3-May-2023)

Ref Expression
Assertion n2dvds1 ¬21

Proof

Step Hyp Ref Expression
1 halfnz ¬12
2 1z 1
3 evend2 12112
4 2 3 ax-mp 2112
5 1 4 mtbir ¬21