Inductive set definition

Question

I'm trying to understand this definition:

"The set $y$ is inductive if $∅∈y$ and $x^+∈y$ whenever $x∈y$"

$x^+$ is the successor of $x$, defined as $x^+=x∪\{x\}$

it's a simple definition but i think it's a little ambiguous between:

1. The set $y$ is inductive if ($∅∈y$) and ($x^+∈y$ whenever $x∈y$)
2. The set $y$ is inductive if ($∅∈y$ and $x^+∈y$) whenever $x∈y$

which one is it?