<t>Hi,I wonder if anyone could clarify why the american call (no divs) is equal to the european call, ie why isn't there any optimal early exercise time ?I can see taht from a mathematical point of vue, but not really from intuition and market feeling.I read an interesting appraoch in Taleb's book "...

thanks alan !i'll go and check on your book

hi everyonei'm wondering if a mean reverting vol SABR model exists (i mean, with a closed form solution as the standard SABR)can anyone provide me with relevant references if they exist ?Thanks !!