Possessive apostrophe

"algorithm complexity"

or

"algorithm's complexity"

?

BTW how do I edit my previous posts?

It is OK in general to use the possessive that way, but in formal writing it's better not to.

the complexity of the algorithm

the rigidity and smoothness of the deformation

You cannot edit your post after a certain amount of time has elapsed. Any editing has to be done right away. That stops people from removing or changing things that would make the replies confusing.

Yes, I'm talking about formal writing. What do you mean by use it that way?

Zohar LeviWhat do you mean by use it that way?

Right. I was unclear. I meant to use the possessive with the inanimate.

the car's paint
the screwdriver's tip
my left shoe's laces

Okay, so you think that "X of Y" is better and more formal than "Y's X", although my English teacher said that the second form is more sophisticated and thus better. In any case, let's consider only the second form "Y's X". When should I add the "'s"?

Does:

the car paint
the screwdriver tip
my left shoe laces

is wrong, has a different meaning, or it's okay but le

EDIT prev: omit the is on the last sentence, and I still can't edit my post even seconds after submission.

We play that by ear. To take your three examples, "the car paint" does not work if you mean the paint that is on the car. "Car paint" would be paint that is intended for use on cars. "The screwdriver tip" is fine in the right context. "My left shoe laces" does not work for two reasons. "Shoelace" is one word, not two, so that's a problem, and "left" wants to attach to "laces", not what is meant.