Symmetry lemmas for the permutation tactics. These rewrite the geometric
primitives (area, colinear, triangle, length, angle, SameSide,
diffside, para) under permutations of their point arguments, and serve as
the building blocks for the perm/perma/linperm tactics defined in
PermTactics.
theorem
SyntheticEuclid4.ss21
[i : IncidenceGeometry]
{a b : IncidenceGeometry.Point}
{L : IncidenceGeometry.Line}
:
theorem
SyntheticEuclid4.ds21
[i : IncidenceGeometry]
{a b : IncidenceGeometry.Point}
{L : IncidenceGeometry.Line}
: