Mercuryville, California Mercuryville, California Mercuryville, California is a ghost town in the Mayacamas Mountains along The Geysers road. Mercuryville was founded in 1874, after cinnabar, a mercury bearing ore, was discovered in eastern Sonoma County around 1870. Mercury is a dense liquid metal that can be used to separate gold from other less dense materials and the California Gold Rush, which had begun only 20 years earlier, increased the demand and price of mercury to $1 a pound, making extracting the ore profitable, and prompting a short-lived mercury rush in the 1870s. When the price of ore dropped within a few years,
Ore extension which means that "δ" is a homomorphism of abelian groups satisfying Then the Ore extension "R"["x";"σ","δ"], also called a skew polynomial ring, is the noncommutative ring obtained by giving the ring of polynomials "R"["x"] a new multiplication, subject to the identity If "δ" = 0 (i.e., is the zero map) then the Ore extension is denoted "R"["x"; "σ"]. If "σ" = 1 (i.e., the identity map) then the Ore extension is denoted "R"["x","δ"] and is called a differential polynomial ring. The Weyl algebras are Ore extensions, with "R" any commutative polynomial ring, "σ" the identity ring endomorphism, and "δ" the