Skew binary number system non-zero digits, a form called the sparse representations of numbers by Okasaki, incrementation and decrementation can be performed in constant time. Other arithmetic operations are performed by switching between the skew binary representation and the binary representation. Given a skew binary number, its value can be computed by a loop, computing the successive values of formula_4 and adding it once or twice for each formula_5 such that the formula_5th digit is 1 or 2 respectively. A more efficient method is now given, with only bit representation and one substraction. The skew binary number of the form formula_7 without 2 and
Contact binary Contact binary In astronomy, a contact binary is a binary star system whose component stars are so close that they touch each other or have merged to share their gaseous envelopes. A binary system whose stars share an envelope may also be called an overcontact binary. Almost all known contact binary systems are eclipsing binaries; eclipsing contact binaries are known as W Ursae Majoris variables, after their type star, W Ursae Majoris. Contact binaries are sometimes confused with common envelopes. However, whereas the configuration of two touching stars in a contact binary has a typical lifetime of millions to billions