Seventh Homework Set Answers

2. From the diagram we see
(dt1, dY1) = (1/4, 3/4), (dt2, dY2) = (1/2, -1/2), (dt3, dY3) = (1/8, 1/4), (dt4, dY4) = (1/8, 1/2)
(a) The Holder exponents of this generator are
H1 = Log(3/4)/Log(1/4) = 1 - Log(3)/Log(4)
H2 = Log(1/2)/Log(1/2) = 1
H3 = Log(1/4)/Log(1/8) = 2/3
H4 = Log(1/2)/Log(1/8) = 1/3
Because the coarse Holder exponents are different, this is a multifractal cartoon.
(b) To find the trading time generator, first solve
1 = |dY1|D + |dY2|D + |dY3|D + |dY4|D = (3/4)D + (1/2)D + (1/4)D + (1/2)D
The solution is D = 2.22655, so the trading time generators are
dT1 = |dY1|D = (3/4)2.2655 = 0.527
dT2 = |dY2|D = (1/2)2.2655 = 0.214
dT3 = |dY3|D = (1/4)2.2655 = 0.0457
dT4 = |dY4|D = (1/2)2.2655 = 0.214

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