|
Palindromes
A palindrome ( /ˈpæl.ɪn.droʊm/) is a word, number, phrase, or other sequence of symbols that reads the same backwards as forwards, such as ''madam'' or '' racecar'', the date " 02/02/2020" and the sentence: "A man, a plan, a canal – Panama". The 19-letter Finnish word ''saippuakivikauppias'' (a soapstone vendor) is the longest single-word palindrome in everyday use, while the 12-letter term ''tattarrattat'' (from James Joyce in '' Ulysses'') is the longest in English. The word ''palindrome'' was introduced by English poet and writer Henry Peacham in 1638.Henry Peacham, ''The Truth of our Times Revealed out of One Mans Experience'', 1638p. 123 The concept of a palindrome can be dated to the 3rd-century BCE, although no examples survive. The earliest known examples are the 1st-century CE Latin acrostic word square, the Sator Square (which contains both word and sentence palindromes), and the 4th-century Greek Byzantine sentence palindrome '' nipson anomemata me monan o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ambigram Palindrome ΝΙΨΟΝΑΝΟΜΗΜΑΤΑΜΗΜΟΝΑΝΟΨΙΝ (Wash Your Sins, Not Only Your Face, In Greek)
An ambigram is a calligraphic composition of glyphs (letters, numbers, symbols or other shapes) that can yield different meanings depending on the orientation of observation. Most ambigrams are visual palindromes that rely on some kind of symmetry, and they can often be interpreted as visual puns. The term was coined by Douglas Hofstadter in 1983–1984. Most often, ambigrams appear as visually symmetrical words. When flipped, they remain unchanged, or they mutate to reveal another Semantics, meaning. "Half-turn" ambigrams undergo a point reflection (180-degree rotational symmetry) and can be read upside down (for example, the word "swims"), while mirror ambigrams have axial symmetry and can be read through a reflective surface like a mirror. Many other types of ambigrams exist. Ambigrams can be constructed in various Written language, languages and alphabets, and the notion often extends to numbers and other symbols. It is a recent interdisciplinary concept, combining Visual arts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palindromic Sequence
A palindromic sequence is a nucleic acid sequence in a double-stranded DNA or RNA molecule whereby reading in a certain direction (e.g. 5' to 3') on one strand is identical to the sequence in the same direction (e.g. 5' to 3') on the complementary strand. This definition of palindrome thus depends on complementary strands being palindromic of each other. The meaning of palindrome in the context of genetics is slightly different from the definition used for words and sentences. Since a double helix is formed by two paired antiparallel strands of nucleotides that run in opposite directions, and the nucleotides always pair in the same way (adenine (A) with thymine (T) in DNA or uracil (U) in RNA; cytosine (C) with guanine (G)), a (single-stranded) nucleotide sequence is said to be a palindrome if it is equal to its reverse complement. For example, the DNA sequence ACCTAGGT is palindromic with its nucleotide-by-nucleotide complement TGGATCCA because reversing the order of the n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palindromic Number
A palindromic number (also known as a numeral palindrome or a numeric palindrome) is a number (such as 16361) that remains the same when its digits are reversed. In other words, it has reflectional symmetry across a vertical axis. The term ''palindromic'' is derived from palindrome, which refers to a word (such as ''rotor'' or ''racecar'') whose spelling is unchanged when its letters are reversed. The first 30 palindromic numbers (in decimal) are: : 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 44, 55, 66, 77, 88, 99, 101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 202, ... . Palindromic numbers receive most attention in the realm of recreational mathematics. A typical problem asks for numbers that possess a certain property ''and'' are palindromic. For instance: * The palindromic primes are 2, 3, 5, 7, 11, 101, 131, 151, ... . * The palindromic square numbers are 0, 1, 4, 9, 121, 484, 676, 10201, 12321, ... . In any base there are infinitely many palindromic numbers, since ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sator Square
The Sator Square (or Rotas-Sator Square or Templar Magic Square) is a two-dimensional acrostic class of word square containing a five-word Latin palindrome. The earliest squares were found at Roman-era sites, all in ROTAS-form (where the top line is "ROTAS", not "SATOR"), with the earliest discovery at Pompeii (and also likely pre-AD 62). The earliest square with Christian-associated imagery dates from the sixth century. By the Middle Ages, Sator squares had been found across Europe, Asia Minor, and North Africa. In 2022, the ''Encyclopedia Britannica'' called it "the most familiar lettered square in the Western world". A significant volume of academic research has been published on the square, but after more than a century, there is no consensus on its origin and meaning. The discovery of the "Paternoster theory" in 1926 led to a brief consensus among academics that the square was created by early Christians, but the subsequent discoveries at Pompeii led many academics to b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Twosday
Twosday was an unofficial one-time secular observance held on Tuesday, February 22, 2022, characterized as a fad. The name is a portmanteau of ''two'' and ''Tuesday'', deriving from the fact that the digits of the date form a numeral palindrome marked by exclusivity or prevalence of the digit 2—when written in different numerical date formats, such as: , 22/2/22 and 2/22/22. It is also an ambigram. In countries that apply the ISO 8601 international standard for the calendar, there is an additional congruence as Tuesday is the second day of the week under this scheme. Anticipation The attraction to the date is due to apophenia. Twosday was described by '' How Stuff Works'' as an example of humans being conditioned under societal institutions to notice only some while ignoring other coincidences that surround them. Attraction to numerology was cited as a reason as well. According to University of Portland professor Aziz Inan, the palindrome is one of the "ubiquitous p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regular Language
In theoretical computer science and formal language theory, a regular language (also called a rational language) is a formal language that can be defined by a regular expression, in the strict sense in theoretical computer science (as opposed to many modern regular expression engines, which are Regular expression#Patterns for non-regular languages, augmented with features that allow the recognition of non-regular languages). Alternatively, a regular language can be defined as a language recognised by a finite automaton. The equivalence of regular expressions and finite automata is known as Kleene's theorem (after American mathematician Stephen Cole Kleene). In the Chomsky hierarchy, regular languages are the languages generated by regular grammar, Type-3 grammars. Formal definition The collection of regular languages over an Alphabet (formal languages), alphabet Σ is defined recursively as follows: * The empty language ∅ is a regular language. * For each ''a'' ∈ Σ (''a'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Automata Theory
Automata theory is the study of abstract machines and automata, as well as the computational problems that can be solved using them. It is a theory in theoretical computer science with close connections to cognitive science and mathematical logic. The word ''automata'' comes from the Greek word αὐτόματος, which means "self-acting, self-willed, self-moving". An automaton (automata in plural) is an abstract self-propelled computing device which follows a predetermined sequence of operations automatically. An automaton with a finite number of states is called a finite automaton (FA) or finite-state machine (FSM). The figure on the right illustrates a finite-state machine, which is a well-known type of automaton. This automaton consists of states (represented in the figure by circles) and transitions (represented by arrows). As the automaton sees a symbol of input, it makes a transition (or jump) to another state, according to its transition function, which takes the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alphabet
An alphabet is a standard set of letter (alphabet), letters written to represent particular sounds in a spoken language. Specifically, letters largely correspond to phonemes as the smallest sound segments that can distinguish one word from another in a given language. Not all writing systems represent language in this way: a syllabary assigns symbols to spoken syllables, while logographies assign symbols to words, morphemes, or other semantic units. The first letters were invented in Ancient Egypt to serve as an aid in writing Egyptian hieroglyphs; these are referred to as Egyptian uniliteral signs by lexicographers. This system was used until the 5th century AD, and fundamentally differed by adding pronunciation hints to existing hieroglyphs that had previously carried no pronunciation information. Later on, these phonemic symbols also became used to transcribe foreign words. The first fully phonemic script was the Proto-Sinaitic script, also descending from Egyptian hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Context-free Language
In formal language theory, a context-free language (CFL), also called a Chomsky type-2 language, is a language generated by a context-free grammar (CFG). Context-free languages have many applications in programming languages, in particular, most arithmetic expressions are generated by context-free grammars. Background Context-free grammar Different context-free grammars can generate the same context-free language. Intrinsic properties of the language can be distinguished from extrinsic properties of a particular grammar by comparing multiple grammars that describe the language. Automata The set of all context-free languages is identical to the set of languages accepted by pushdown automata, which makes these languages amenable to parsing. Further, for a given CFG, there is a direct way to produce a pushdown automaton for the grammar (and thereby the corresponding language), though going the other way (producing a grammar given an automaton) is not as direct. Examples An e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sotades
Sotades (; 3rd century BC) was an Ancient Greek poet. Sotades was born in Maroneia, either the one in Thrace, or in Crete. He lived in Alexandria during the reign of Ptolemy II Philadelphus (285–246 BC). The city was at that time a remarkable center of learning, with a great deal of artistic and literary activity, including epic poetry and the Great Library. Only a few genuine fragments of his work have been preserved; those in Stobaeus are generally considered spurious. Ennius translated some poems of this kind, included in his book of satires under the name of Sota. He had a son named Apollonius. He has been credited with the invention of the palindrome. Sotades was the chief representative of the writers of obscene and even satirical poems, called "kinaidoi" (), composed in the Ionic dialect and in the metre named after him. One of his poems attacked Ptolemy II Philadelphus's marriage to his own sister Arsinoe II, from which came the infamous line: "You're sticking you ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sator Square At Oppède
Sator may refer to: * Šator, a mountain in Bosnia and Herzegovina * Sator (band), a Swedish band * ''Sator'' (film), a 2020 American supernatural horror film * ''Sator'' (lizard), a genus of lizard * Sator bean (''Parkia speciosa''), or stink bean, a bean with a strong smell popular in South East Asian cuisine * Sator Square The Sator Square (or Rotas-Sator Square or Templar Magic Square) is a two-dimensional acrostic class of word square containing a five-word Latin palindrome. The earliest squares were found at Roman-era sites, all in ROTAS-form (where the top l ... (or Rotas Square), a first-century word square containing a five-word Latin palindrome * Sator (the "Sower"), a minor Roman agricultural deity or cult title * Andrei Sator, a character from the film '' Tenet'' People with the surname * Klaus Sator (born 1956), German historian * László Sátor (born 1953), Hungarian racewalker * Ted Sator (born 1949), American ice hockey coach {{disambiguation, su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crab Canon
A crab canon (also known by the Latin form of the name, ''canon cancrizans''; as well as ''retrograde canon'', ''canon per recte et retro'' or ''canon per rectus et inversus'')Kennedy, Michael (ed.). 1994. "Canon". The Oxford Dictionary of Music, associate editor, Joyce Bourne. Oxford and New York: Oxford University Press. . is an arrangement of two musical lines that are complementary and backward. If the two lines were placed next to each other (as opposed to stacked), the lines would form something conceptually similar to a palindrome. The name 'crab' refers to the fact that crabs are known to walk backward (although they can also walk forward and sideways). It originally referred to a kind of canon in which one line is played backward (e.g. FABACEAE played simultaneously with EAECABAF). An example is found in J. S. Bach's '' The Musical Offering'', which also contains a table canon ("Quaerendo invenietis"), which combines retrogression with inversion by having one player ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
