Metamath Proof Explorer


Theorem rerecrecd

Description: A number is equal to the reciprocal of its reciprocal. (Contributed by SN, 2-Apr-2026)

Ref Expression
Hypotheses sn-rereccld.a φ A
sn-rereccld.z φ A 0
Assertion rerecrecd Could not format assertion : No typesetting found for |- ( ph -> ( 1 /R ( 1 /R A ) ) = A ) with typecode |-

Proof

Step Hyp Ref Expression
1 sn-rereccld.a φ A
2 sn-rereccld.z φ A 0
3 1 2 rerecid2d Could not format ( ph -> ( ( 1 /R A ) x. A ) = 1 ) : No typesetting found for |- ( ph -> ( ( 1 /R A ) x. A ) = 1 ) with typecode |-
4 1red φ 1
5 1 2 sn-rereccld Could not format ( ph -> ( 1 /R A ) e. RR ) : No typesetting found for |- ( ph -> ( 1 /R A ) e. RR ) with typecode |-
6 1 2 rerecne0d Could not format ( ph -> ( 1 /R A ) =/= 0 ) : No typesetting found for |- ( ph -> ( 1 /R A ) =/= 0 ) with typecode |-
7 4 1 5 6 redivmuld Could not format ( ph -> ( ( 1 /R ( 1 /R A ) ) = A <-> ( ( 1 /R A ) x. A ) = 1 ) ) : No typesetting found for |- ( ph -> ( ( 1 /R ( 1 /R A ) ) = A <-> ( ( 1 /R A ) x. A ) = 1 ) ) with typecode |-
8 3 7 mpbird Could not format ( ph -> ( 1 /R ( 1 /R A ) ) = A ) : No typesetting found for |- ( ph -> ( 1 /R ( 1 /R A ) ) = A ) with typecode |-