Pikuach nefesh (Hebrew: פיקוח נפש), which means "saving a soul" or "saving a life," is the principle in Halakha (Jewish law) that the preservation of human life overrides virtually any other religious rule of Judaism. In the event that a person is in critical danger, most mitzvot become inapplicable if they would hinder the ability to save oneself or someone else. However, there are certain exceptions; some rules and commandments may not be broken under any circumstances and thus may require an act of self-sacrifice. == Origin and interpretation == === Biblical source === The Torah, in Leviticus...

In mathematics, Volterra's function, named for Vito Volterra, is a real-valued function V defined on the real line R with the following curious combination of properties: V is differentiable everywhere The derivative V ′ is bounded everywhere The derivative is not Riemann-integrable. == Definition and construction == The function is defined by making use of the Smith–Volterra–Cantor set and an infinite number or "copies" of sections of the function defined by f ( x ) = {...

Divine Proportions: Rational Trigonometry to Universal Geometry is a 2005 book by the mathematician Norman J. Wildberger on a proposed alternative approach to Euclidean geometry and trigonometry, called rational trigonometry. The book advocates replacing the usual basic quantities of trigonometry, Euclidean distance and angle measure, by squared distance and the square of the sine of the angle, respectively. This is logically equivalent to the standard development (as the replacement quantities can be expressed in terms of the standard ones and vice versa). The author claims his approach holds...