Infinity symbol Infinity symbol The infinity symbol (sometimes called the lemniscate) is a mathematical symbol representing the concept of infinity. The shape of a sideways figure eight has a long pedigree; for instance, it appears in the cross of Saint Boniface, wrapped around the bars of a Latin cross. However, John Wallis is credited with introducing the infinity symbol with its mathematical meaning in 1655, in his "De sectionibus conicis". Wallis did not explain his choice of this symbol, but it has been conjectured to be a variant form of a Roman numeral for 1,000 (originally CIƆ, also CƆ), which was sometimes
Spin (physics) state and a spin-4 particle should be rotated 90 degrees to bring it back to the same quantum state. The spin-2 particle can be analogous to a straight stick that looks the same even after it is rotated 180 degrees and a spin 0 particle can be imagined as sphere, which looks the same after whatever angle it is turned through. Spin obeys commutation relations analogous to those of the orbital angular momentum: where is the Levi-Civita symbol. It follows (as with angular momentum) that the eigenvectors of and (expressed as kets in the total basis) are: The spin raising