Quietly, though, something less predictable has happened. Bernie Sanders has become â by a considerable margin â the most popular politician in the United States. Earlier this month, an Economist/YouGov poll found that 59 percent of Americans have a favorable opinion of Sanders, while only 33 percent hold an unfavorable one.
A letterhead is the heading at the top of a sheet of letter paper (stationery). That heading usually consists of a name and an address, and a logo or corporate design, and sometimes a background pattern. The term letterhead is often used to refer to the whole sheet imprinted with such a heading.
Sigma is the eighteenth letter of the ancient Greek alphabet. As an upper case letter (), it is used as a symbol for sums and series. As a lower case letter () it is a prefix used in several contexts to indicate that a term is referred in some way to countable unions.