Survival probability from an absorbing transition density
= Survival probability from an absorbing transition density
{title2=$S(t|x_i)=\int_DK_D(x,t|x_i,0)\,dx$}
A transition density with absorbing boundaries counts the joint event of survival up to <time> $t$ and a specified final <position>. Its integrated <mass> is <survival probability>, not generally one. Dividing by that <mass> gives the endpoint density conditional on survival, a different object.