Talk:Focaloid

In the section of mathematical definition, when thin focaloids are explained...

Shouldn't it be in the limit of lambda tends to 0?

Because in that case, both surfaces are so closed to each other that the volume between them is very "thin" (in the limit, 0, and both shells are the same). I had never heard about focaloids, that's why i don't want to change anything, i need a second opinion :) --Piockñec (talk) 16:53, 6 January 2015 (UTC)