Battle axeA battle axe (also battle-axe, battle ax, or battle-ax) is an axe specifically designed for combat. Battle axes were specialized versions of utility axes. Many were suitable for use in one hand, while others were larger and were deployed two-handed. Axes designed for warfare ranged in weight from just over , and in length from just over to upwards of , as in the case of the Danish axe or the sparth axe. Cleaving weapons longer than 150 cm would arguably fall into the category of polearms.
Topological quantum numberIn physics, a topological quantum number (also called topological charge) is any quantity, in a physical theory, that takes on only one of a discrete set of values, due to topological considerations. Most commonly, topological quantum numbers are topological invariants associated with topological defects or soliton-type solutions of some set of differential equations modeling a physical system, as the solitons themselves owe their stability to topological considerations.
Human Development IndexThe Human Development Index (HDI) is a statistical composite index of life expectancy, education (mean years of schooling completed and expected years of schooling upon entering the education system), and per capita income indicators, which is used to rank countries into four tiers of human development. A country scores a higher level of HDI when the lifespan is higher, the education level is higher, and the gross national income GNI (PPP) per capita is higher.
