Palindrome (; "again") and ' (; "way, direction"). Palindromes date back at least to 79 AD, as a palindrome was found as a graffito at Herculaneum, a city buried by ash in that year. This palindrome, called the Sator Square, consists of a sentence written in Latin: "Sator Arepo Tenet Opera Rotas" ("The sower Arepo holds with effort the wheels"). It is remarkable for the fact that the first letters of each word form the first word, the second letters form the second word, and so forth. Hence, it can be arranged into a word square that reads in four different
Splitting principle The fact that formula_3 is injective means that any equation which holds in formula_4 (say between various Chern classes) also holds in formula_5. The point is that these equations are easier to understand for direct sums of line bundles than for arbitrary vector bundles, so equations should be understood in formula_6 and then pushed down to formula_7. Under the splitting principle, characteristic classes for complex vector bundles correspond to symmetric polynomials in the first Chern classes of complex line bundles; these are the Chern classes. Splitting principle In mathematics, the splitting principle is a technique used to reduce questions about