@[class]
- not_char_two : myfld.one .+ myfld.one ≠ myfld.zero
theorem
add_two_halves
(f : Type)
[myfld f]
[fld_not_char_two f] :
(myfld.reciprocal (two f) _) .+ (myfld.reciprocal (two f) _) = myfld.one
@[class]
- not_char_three : three f ≠ myfld.zero
theorem
six_ne_zero
(f : Type)
[myfld f]
[fld_not_char_two f]
[fld_not_char_three f] :
six f ≠ myfld.zero
theorem
two_x_div_two
(f : Type)
[myfld f]
[fld_not_char_two f]
(a : f) :
(myfld.reciprocal (two f) fld_not_char_two.not_char_two) .* (a .+ a) = a