Metamath Proof Explorer


Theorem div1

Description: A number divided by 1 is itself. (Contributed by NM, 9-Jan-2002) (Proof shortened by Mario Carneiro, 27-May-2016)

Ref Expression
Assertion div1 AA1=A

Proof

Step Hyp Ref Expression
1 mullid A1A=A
2 ax-1cn 1
3 ax-1ne0 10
4 2 3 pm3.2i 110
5 divmul AA110A1=A1A=A
6 4 5 mp3an3 AAA1=A1A=A
7 6 anidms AA1=A1A=A
8 1 7 mpbird AA1=A