$
f(x)=x^2 \
f_(x y)(x)=x^(2-y) \
pi approx 3.14 \
2 dot 4 <= 8 \
1 < 2 > 1, 2 != 3 \
1 lt 2 gt 1, 2 eq.not 3, 4 lt.eq 8 \
(f^(-1)_x) \
frac(2,4) + frac(1, frac(5,17)) \
sqrt(16) = 4, root(4, 64) = 2
$