  We present a short exposition of the following results by S. Parsa.
  Let $L$ be a graph such that the join $L*\{1,2,3\}$ (i.e. the union of three
cones over $L$ along their common bases) piecewise linearly (PL) embeds into
$\mathbb R^4$. Then $L$ admits a PL embedding into $\mathbb R^3$ such that any
two disjoint cycles have zero linking number.
  There is $C$ such that every 2-dimensional simplicial complex having $n$
vertices and embeddable into $\mathbb R^4$ contains less than $Cn^{8/3}$
simplices of dimension 2.
  We also present the analogue of the second result for intrinsic linking.
