Seifert algorithm
= Seifert algorithm
{c}
Apply the <oriented smoothing> to every crossing of an oriented <knot diagram>, fill the resulting <Seifert circles> by disjoint disks at suitable heights, and reconnect them by twisted bands at the original crossings. The boundary is the original <knot>. If the connected surface has $s$ disks and $c$ bands, its <Euler characteristic> is $s-c$ and its <genus> is $(1-s+c)/2$.