Metamath Proof Explorer


Theorem lmiiso

Description: The line mirroring function is an isometry, i.e. it is conserves congruence. Because it is also a bijection, it is also a motion. Theorem 10.10 of Schwabhauser p. 89. (Contributed by Thierry Arnoux, 11-Dec-2019)

Ref Expression
Hypotheses ismid.p
|- P = ( Base ` G )
ismid.d
|- .- = ( dist ` G )
ismid.i
|- I = ( Itv ` G )
ismid.g
|- ( ph -> G e. TarskiG )
ismid.1
|- ( ph -> G TarskiGDim>= 2 )
lmif.m
|- M = ( ( lInvG ` G ) ` D )
lmif.l
|- L = ( LineG ` G )
lmif.d
|- ( ph -> D e. ran L )
lmiiso.1
|- ( ph -> A e. P )
lmiiso.2
|- ( ph -> B e. P )
Assertion lmiiso
|- ( ph -> ( ( M ` A ) .- ( M ` B ) ) = ( A .- B ) )

Proof

Step Hyp Ref Expression
1 ismid.p
 |-  P = ( Base ` G )
2 ismid.d
 |-  .- = ( dist ` G )
3 ismid.i
 |-  I = ( Itv ` G )
4 ismid.g
 |-  ( ph -> G e. TarskiG )
5 ismid.1
 |-  ( ph -> G TarskiGDim>= 2 )
6 lmif.m
 |-  M = ( ( lInvG ` G ) ` D )
7 lmif.l
 |-  L = ( LineG ` G )
8 lmif.d
 |-  ( ph -> D e. ran L )
9 lmiiso.1
 |-  ( ph -> A e. P )
10 lmiiso.2
 |-  ( ph -> B e. P )
11 eqid
 |-  ( ( pInvG ` G ) ` ( ( A ( midG ` G ) ( M ` A ) ) ( midG ` G ) ( B ( midG ` G ) ( M ` B ) ) ) ) = ( ( pInvG ` G ) ` ( ( A ( midG ` G ) ( M ` A ) ) ( midG ` G ) ( B ( midG ` G ) ( M ` B ) ) ) )
12 eqid
 |-  ( ( A ( midG ` G ) ( M ` A ) ) ( midG ` G ) ( B ( midG ` G ) ( M ` B ) ) ) = ( ( A ( midG ` G ) ( M ` A ) ) ( midG ` G ) ( B ( midG ` G ) ( M ` B ) ) )
13 1 2 3 4 5 6 7 8 9 10 11 12 lmiisolem
 |-  ( ph -> ( ( M ` A ) .- ( M ` B ) ) = ( A .- B ) )