scholarly journals Fat tails and black swans: Exact results for multiplicative processes with resets

2020 ◽  
Vol 30 (3) ◽  
pp. 033104 ◽  
Author(s):  
D. H. Zanette ◽  
S. Manrubia
Keyword(s):  
Exact Results ◽  
Fat Tails ◽  
Black Swans ◽  
Multiplicative Processes

Worshiping Math

2019 ◽  
pp. 65-84
Author(s):  
Gary Smith ◽  
Jay Cordes
Keyword(s):  
Data Mining ◽  
Normal Distribution ◽  
Common Sense ◽  
Fat Tails ◽  
Explanatory Variables ◽  
Good Data ◽  
Black Swans ◽  
The People ◽  
Invaluable Tool ◽  
Mining Tools

Data-mining tools, in general, tend to be mathematically sophisticated, yet often make implausible assumptions. For example, analysts often assume a normal distribution and disregard the fat tails that warn of “black swans.” Too often, the assumptions are hidden in the math and the people who use the tools are more impressed by the math than curious about the assumptions. Instead of being blinded by math, good data scientists use explanatory variables that make sense. Good data scientists use math, but do not worship it. They know that math is an invaluable tool, but it is not a substitute for common sense, wisdom, or expertise.

scholarly journals Trading and Fat Tails

2016 ◽  
Vol 1 (1) ◽  
pp. 2 ◽  
Author(s):  
Robert I Webb
Keyword(s):  
Fat Tails ◽  
Price Changes ◽  
Economic Information ◽  
Black Swans ◽  
Fundamental Information

Sudden, large price changes periodically occur in speculative markets. Many of these large price moves simply reflect the market’s reaction to new fundamental economic information-- as financial theory would predict. However, some of the most extreme price moves—often characterized (albeit incorrectly) as “Black Swans” in popular parlance--reflect more the predictable behavior of traders in certain situations or poorly designed market microstructures than the arrival of new fundamental information. These trading-induced price moves have important implications for practitioners, policymakers and academics alike.

Erratum - Frustration in periodic systems : exact results for some 2D ising models

1979 ◽  
Vol 40 (10) ◽  
pp. 1024-1024
Author(s):  
G. André ◽  
R. Bidaux ◽  
J.-P. Carton ◽  
R. Conte ◽  
L. de Seze
Keyword(s):  
Ising Models ◽  
Periodic Systems ◽  
Exact Results

Almost empty polygons

2003 ◽  
Vol 40 (3) ◽  
pp. 269-286 ◽  
Author(s):  
H. Nyklová
Keyword(s):  
Exact Results ◽  
Point Sets ◽  
Planar Point ◽  
Convex Position ◽  
Vertex Set ◽  
Point Set ◽  
Empty Polygons

In this paper we study a problem related to the classical Erdos--Szekeres Theorem on finding points in convex position in planar point sets. We study for which n and k there exists a number h(n,k) such that in every planar point set X of size h(n,k) or larger, no three points on a line, we can find n points forming a vertex set of a convex n-gon with at most k points of X in its interior. Recall that h(n,0) does not exist for n = 7 by a result of Horton. In this paper we prove the following results. First, using Horton's construction with no empty 7-gon we obtain that h(n,k) does not exist for k = 2(n+6)/4-n-3. Then we give some exact results for convex hexagons: every point set containing a convex hexagon contains a convex hexagon with at most seven points inside it, and any such set of at least 19 points contains a convex hexagon with at most five points inside it.

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