Palindrome: Encyclopedia - Palindrome

Palindrome

A palindrome is a word, phrase, number or other sequence of units (such as a strand of DNA) that has the property of reading the same in either direction (the adjustment of punctuation and spaces between words is generally permitted). The word "palindrome" comes from the Greek palin (παλιν) "back" and dromos (δρóμος) "way, direction". Composing literature in palindromes is an example of constrained writing.

Palindrome - History

According to Bill Bryson's Mother Tongue: English & How It Got That Way (p. 227): "Palindromes … are at least 2,000 years old". The ancient Greeks often inscribed the palindrome "ΝΙΨΟΝΑΝΟΜΗΜΑΤΑΜΗΜΟΝΑΝΟΨΙΝ" on fountains; in mixed case with modern accents and divided into words this reads "Νίψον ανομήματα μη μόναν όψιν" ("Nipson anomēmata mē monan opsin"), meaning "Wash the sin as well as the face" (ps, ψ, is the single Greek letter psi).

The Romans enjoyed palindromes too, as demonstrated by "In girum imus nocte et consumimur igni" ("We enter the circle at night and are consumed by fire"), which was said to describe the behavior of moths. The Latin palindrome "Sator Arepo Tenet Opera Rotas" is remarkable for the fact that it also reproduces itself if one forms a word from the first letters, then the second letters and so forth. Hence it can be arranged into a word square that reads in four different ways: horizontally or vertically from top left to bottom right; and horizontally or vertically from bottom right to top left.

  S A T O R
  A R E P O
  T E N E T
  O P E R A
  R O T A S

Translation is problematic as the sentence is grammatically flawed; for further discussion, see separate article.

Palindrome - Palindromes in different languages

Palindromes occur in many western languages, but they are particularly prevalent in English due to the wide variety of reversible letter pairs within words. Finnish, however, has been described as "the language of palindromes."

Japanese palindromes, called kaibun, rely on the hiragana syllabary. An example is the word shinbunshi (in syllables shi-n-bu-n-shi), meaning "newspaper". The Japanese syllabary makes it possible to construct very long palindromes.

Chinese palindromes are relatively easy to create due to the structure of written Chinese. For example: 我愛媽媽,媽媽愛我 ("I love Mom; Mom loves me") — usually the first palindrome learned by Chinese children. Numerous palindromes can be created by replacing "媽媽"(Mom) with any person. As a result, only very special palindromes are worth mentioning.

Palindrome - Types of palindrome

Palindrome - Symmetry by characters

The most familiar palindromes, in English at least, are character-by-character: the written characters read the same backwards as forwards. Palindromes may consist of a single word (such as civic), a phrase or sentence (Was it a cat I saw?), or a longer passage of text. Spaces, punctuation and case are usually ignored. a one of language of india "malayalam"

Palindrome - Symmetry by words

Some palindromes use words as units rather than letters. An example is You can cage a swallow, can't you, but you can't swallow a cage, can you?.

Palindrome - Symmetry by lines

Still other palindromes take the line as the unit. The poem Doppelganger, composed by James A. Lindon, is an example.

The dialogue "Crab Canon" in Douglas Hofstadter's Gödel, Escher, Bach is nearly a line-by-line palindrome. The second half of the dialog consists, with some very minor changes, of the same lines as the first half, but in reverse order and spoken by the opposite characters (i.e., lines spoken by Achilles in the first half are spoken by the Tortoise in the second, and vice versa). In the middle is a non-symmetrical line spoken by the Crab, who enters and spouts some nonsense, apparently triggering the reversal. The structure is modeled after J. S. Bach's crab canon.

Another sentence is supposed to be said by Napolean "Able was I ere, I saw Elba"

Palindrome - Symmetry by sound

Some palindromes are by sound, such as the Hungarian A bátya gatyába ("The brother in underpants"), or the Japanese Ta-ke-ya-bu ya-ke-ta (竹薮焼けた) ("A bamboo grove has been burned").

Palindrome - Numbers

See main article: Palindromic number

Palindrome - Dates and times

Palindromes can also be constructed using dates and times. The exact dates and times may differ according to the local style (for example, whether the month or day is written first). For example:

• 12/02/2021 for 12th February 2021, using the DD/MM/YYYY format; or 2nd December 2021 using the MM/DD/YYYY format.
• 10/30/2002 03:01 for 30th October 2002, 3:01 AM, using the MM/DD/YYYY HH:MM format.

Palindrome - In music

On his 2003 album Poodle Hat, the comedy singer "Weird Al" Yankovic included a song called Bob composed entirely of rhyming palindromes. The name Bob is itself a palindrome, and is also a reference to Bob Dylan, whose Subterranean Homesick Blues he emulated in both the song's style and the accompanying video.

The singer and guitarist Baby Gramps wrote and performs a song entitled Palindromes. Nerdcore rapper MC Paul Barman, in his song Bleeding Brain Grow from the album Paullelujah, rapped a couple of lines written in palindromes, mostly name-dropping some of his favorite rappers.

The musical duo of John Linnell and John Flansburgh, also known as They Might be Giants, wrote a song related to palindromes called I Palindrome I. The song appears on their album Apollo 18. At one point in the song, the lyrics are the same forwards as backwards: "Son, I am able she said though you scare me, watch, said I, beloved, I said watch me scare you though, said she able am I, son."

The Icelandic band Sigur Rós composed a song on their album Ágætis byrjun which partly sounds the same played forwards or backwards. The notes have a symmetric form, and a reversed version of the music is mixed over the original. The song—named Starálfur—can be downloaded from their website [1].

The interlude from Alban Berg's opera Lulu is a palindrome, as are sections and pieces, in arch form, by many other composers, including James Tenney (swell), and most famously Béla Bartók (and, influenced by him, Steve Reich).

See also crab canon — in classical music, a canon in which one line of the melody is reversed in time and pitch from the other.

Palindrome - Computer programs

Brian Westley wrote a C program for the 1987 International Obfuscated C Code Contest which is a line-by-line palindrome: http://www.ioccc.org/1987/westley.c

Up to the type definitions, here is a compilable palindrome written in Caml:

type 'a elbatum = 'a ;;
type lol = bool ;;
type pop = int ;;
type b = { mutable lol : lol elbatum } ;;
type i = { mutable pop : pop elbatum } ;;

fun erongi lol pop n ->
pop.lol <- let nuf =
erongi ; fun erongi lol pop n -> pop.lol ; ignore
n in
erongi ; lol.pop <- n pop lol ignore nuf ; ignore
= fun tel -> lol.pop
<- n pop lol ignore nuf
;;

Palindrome - URLs

• http://en.wikipedia.org/wiki/ikiw/gro.aidepikiw.ne//:ptth (links back here)

Palindrome - Long palindromes

The longest palindromic word in the Oxford English Dictionary is tattarrattat, coined by James Joyce in Ulysses for a knock on the door. The Guinness Book of Records gives detartrated, the past tense of detartrate, a somewhat contrived chemical term meaning to remove tartrates. The longest "natural" English palindrome is arguably redivider (someone or something that redivides). Malayalam, an Indian language, is of equal length.

Saippuakauppias, Finnish for "soap vendor", is claimed to be the world's longest palindromic word in everyday use.

To celebrate 20:02 02/20 2002, a palindromic day, Peter Norvig wrote on that day a computer program which produced the world's longest palindromic sentence, running to 17,259 words [2].

A long palindrome in English that reads more easily and attempts to flow is reproduced here.

In 1991, Gordon Dow composed a 306 word palindrome titled Dog Sees Ada. This palindrome is famous for using very few contrived words. It is reproduced here.

Palindrome - Biological structures

In most genomes or sets of genetic instructions, palindromic motifs are found. A palindromic DNA sequence can form a hairpin. Palindromic motifs are made by the order of the nucleotides that specify the complex chemicals (proteins) which, as a result of those genetic instructions, the cell is to produce. They have been specially researched in bacterial chromosomes and in the so-called Bacterial Interspersed Mosaic Elements (BIMEs) scattered over them. Recently a research genome sequencing project discovered that many of the bases on the Y chromosome are arranged as palindromes.

Palindrome - Philosophy of nature

Some philosopher-scientists report a palindromic relationship between the astrophysical-biological evolution and the experiencing beings in it. The issue is related with ascertaining if nature is an instrument (as merely a means), instead of having any intrinsic value (an end in itself); and, likewise, if conscious beings are merely a means (one to entropize nature faster) or either possess any intrinsic value. Two possibilities are deemed not indifferent in this regard: either reading the whole set of empirically-found realities or facts makes sense in both directions (palindromic reading of nature), or, rather, that sense can only be ascribed to such a set by reading it in some single direction. A single direction means reading nature in a classic, materialist or idealist sense; both directions' sense means a mirror or reciprocal functionalization, in which each of both realities (mind-possessing living creatures, and astrophysical-biospheric evolution) uses for its own ends the reality that uses it as a means. At stake, therefore, is establishing if axiological readings ascribing a sense to what is found going on in the universe can be obtained in both directions, or not. On this alternative, it is claimed, pivots the possibility of ascertaining, e.g., whether conscious beings are worthier than non-conscious nature, or not - a topic assumed consequential for philosophy, ecology, ecofeminism and biocentric environmental movements, and ethics.

Palindrome - Computation Theory

In Automata Theory, a set of all palindromes in a given alphabet is a typical example of a language which is context-free, but not regular. It is also an example of a context-free language which cannot be accepted by a deterministic pushdown automaton.[3]

Palindrome - Further examples

For numerous further examples of palindromes in a variety of different languages see Palindromic words and Palindromic phrases.

See also

• ambigram
• anagram
• Aoxomoxoa by the Grateful Dead
• "Bob" (from the album Poodle Hat) by "Weird Al" Yankovic
• crab canon
• holorhyme
• pangram
• palindromic number
• semordnilap
• transcription (linguistics)
• word games
• word play

Adapted from the Wikipedia article "Palindrome", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki