# It shows that the Hahn Banach extension is unique.

Suppose $$chi = l _ { infty}$$ Y $$Y = C_ {0}$$. How can I show that if $$y ^ { ast} in Y ^ { ast}$$ Y $$parallel and ^ { ast} parallel$$ = $$1$$So, the standard that prescribes the Hahn Banach extension is unique?