p*****n
发帖数: 758 | 1 if u is real-valued harmonic in D(open unit disc) with |u|<=1 and u(0)=0,
prove that |u|<=(4arctan|z|)/pi. | c*****n
发帖数: 33 | 2 I think you can try in this way. Construct a biholomorphism from the strip -
1
to the unit disc with the origin fixed and then use Schwarz lemma.
【在 p*****n 的大作中提到】
: if u is real-valued harmonic in D(open unit disc) with |u|<=1 and u(0)=0,
: prove that |u|<=(4arctan|z|)/pi.
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