$E1(\underline{A11},A12,A13)$
$\underline{A11}\rightarrow A12\ A13$
$CK:A11$
$3NF:\checkmark$
$E2R(\underline{A21},A22,A23,A11) $
$A21\rightarrow\rightarrow A23=Allowed\ in\ 2NF/3NF/BCNF$
$A21\rightarrow A22\ A11$
$CK:\underline{A21A23}$
$\underbrace{A21\rightarrow A22\ A11}=partial\ dependency$
Therefore Decompose into tables
$(A21,A23)$
$A21\rightarrow\rightarrow A23=Trivial\ MVD$
$CK:\underline{A21A23}$
$(A21,A22,A11)$
$A21\rightarrow A22\ A11$
$CK:A21$
$3NF:\checkmark$