Pewter Pewter Pewter () is a malleable metal alloy. It is traditionally composed of 85–99% tin, mixed with copper, antimony, bismuth, and sometimes silver or lead, although the use of lead is less common today. Copper and antimony act as hardeners while lead is more common in the lower grades of pewter, which have a bluish tint. Pewter has a low melting point, around , depending on the exact mixture of metals. The word "pewter" is probably a variation of the word "spelter", a term for zinc alloys (originally a colloquial name for zinc). Pewter was first used around the beginning
Pivot element Pivot element The pivot or pivot element is the element of a matrix, or an array, which is selected first by an algorithm (e.g. Gaussian elimination, simplex algorithm, etc.), to do certain calculations. In the case of matrix algorithms, a pivot entry is usually required to be at least distinct from zero, and often distant from it; in this case finding this element is called pivoting. Pivoting may be followed by an interchange of rows or columns to bring the pivot to a fixed position and allow the algorithm to proceed successfully, and possibly to reduce round-off error. It is