The property that portfolio choice can be separated into two independent tasks: 1) determination of the optimal risky portfolio , which is a purely mathematical problem, and 2) the personal choice of the best mix of the optimal risky portfolio and the risk-free asset which depends on a person's risk aversion.
SEPARATION PROPERTY
Meaning of SEPARATION PROPERTY in English
Campbell R. Harvey. Hypertextual finance English glossary. Английский словарь гипертекстовых финансов. 2012