Description: The mirroring line is an invariant. (Contributed by Thierry Arnoux, 8-Aug-2020)
| 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 ) | ||
| lmicl.1 | |- ( ph -> A e. P ) | ||
| lmicinv.1 | |- ( ph -> A e. D ) | ||
| Assertion | lmicinv | |- ( ph -> ( M ` A ) = A ) | 
| 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 | lmicl.1 | |- ( ph -> A e. P ) | |
| 10 | lmicinv.1 | |- ( ph -> A e. D ) | |
| 11 | 1 2 3 4 5 6 7 8 9 | lmiinv | |- ( ph -> ( ( M ` A ) = A <-> A e. D ) ) | 
| 12 | 10 11 | mpbird | |- ( ph -> ( M ` A ) = A ) |