I've been crocheting for quite a while now.... LOL but I've never really done lace or anything (doileys don't count as lace I don't think). When I wanted a gap I just did something akin to filet.
(I was never really taught how to crochet... I bought a crochet hook and started doing with it what I had been doing with my fingers since the first time I held yarn. That is not a joke, I swear. ) So I never really learned different stitches unless I wanted/needed a different effect.
So now I am getting ready to convert a fairly popular lace pattern from knit to crochet..... So is there a crochet yarn over? Do you do it just like a knitting y/o and then decrease a stitch later on? :D