What is a Gauss sign? I am reading the paper " _A Method for Extraction of Bronchus Regions from 3D Chest X-ray CT Images by Analyzing Structural Features of the Bronchus_ " by Takayuki KITASAKA, Kensaku MORI, Jun-ichi HASEGAWA and Jun-ichiro TORIWAKI and I run into a term I do not understand: * * * !paper * * * In equation (2), **when we say "[] expresses the Gauss sign", what does it mean?**

From the context (a change of scale using discrete units), this should certainly mean **floor** as on page 5 of Gauss's _Werke_ 2

> per signum $[x]$ exprimemus integrum ipsa $x$ proxime minorem, ita ut $x-[x]$ semper fiat quantitas positiva intra limites $0$ et $1$ sita

i.e. the next lower integer.