It is an abbreviation for Binary Coded Decimal, decimal numbers where each digit is defined by a fixed number of bits which is usually considered four or eight.
7 gives the freezing-point curve of mercury and thallium; here A and E are the melting-points of pure mercury and pure thallium, and the branches AB and ED do not cut each other, but cut an intermediate rounded branch BCD.
The simplest invariant is S = (abc) (abd) (acd) (bcd) cf degree 4, which for the canonical form of Hesse is m(1 -m 3); its vanishing indicates that the form is expressible as a sum of three cubes.
BCD הגייה עם משמעויות, מילים נרדפות, הפכים, תרגומים, משפטים ועוד