palindrome

• 回文構造、回文、パリンドローム

関

palindromic

　 　

WordNet

1. a word or phrase that reads the same backward as forward

PrepTutorEJDIC

1. 回文(前後どちらから読んでも同一に読める語・句・文)

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/07/08 21:32:06」(JST)

wiki ja

[Wiki ja表示]

回文（かいぶん）とは、始めから（通常通り）読んだ場合と終わりから（通常と逆に）読んだ場合とで文字や音節の出現する順番が変わらず、なおかつ、言語としてある程度意味が通る文字列のことで、言葉遊びの一種である。英語では palindrome という。

概要

西暦79年にヴェスヴィオ火山の噴火によって滅亡したヘルクラネウムの街の遺跡に「Sator Arepo Tenet Opera Rotas」という回文が刻まれている事から、回文の起源は少なくとも西暦79年またはそれ以前まで遡る事ができる。英語では「Madam, I'm Adam」（マダム、私はアダムです）のような例が知られている。日本でも「磨かぬ鏡」「竹藪焼けた」など、言葉遊びとして古くからいくつもの例があり、小瀬渺美は安政期に新潟の俳人が刊行した回文俳諧集を挙げて、当時から日本で回文の文化が普及していた可能性を指摘している。

著名な古典的回文として以下のものがある。いずれも五七五七七の短歌律形式をとっている。

• 長き夜の 遠の睡りの 皆目醒め 波乗り船の 音の良きかな
• むら草に くさの名はもし 具はらは なそしも花の 咲くに咲くらむ
• 惜しめとも ついにいつもと 行春は 悔ゆともついに いつもとめしを

回文は前読んでも後ろから読んでも意味が同じものだが、これに対し「gateman」（後ろから読むと「nametag」）のように前から読んだ場合と後ろから読んだ場合で意味が変わるものをsemordnilap（シモードニラップ）と呼ぶ。これはpalindromes（＝回文）を後ろから読んで作られた造語で、「semordnilap」という単語自身がsemordnilapの例になっている。この言葉は論理学者のDmitri A. Borgmannによって作られたとされている。

日本語回文のルールとして、濁音、半濁音、促音、拗音は清音と同一として考えることが多い。すなわち、「は行」と「ば行」と「ぱ行」、「つ」と「っ」、「や」と「ゃ」などは逆から読んだ際に発音が入れ替わっても問題はない。ただし、回文作家の中にはこれを嫌い、発音まで完全に回文にすることにこだわる者もいる。

日本語の回文といえばふつう、かな表記の回文をさす。ローマ字表記日本語の回文については、高木茂男 (1976). 数学遊園地. 講談社. ISBN 9784061178915. に例が見える。漢字表記では日本語の文章として成立しないので、単語（特に固有名詞）で回文とみなすこともある。

1661年（寛文元年）に刊行された『紙屋川水車集』には以下の41文字の回文があり、最長の日本語回文とされていた。現在では1000文字以上の回文も作られている。

• はれけき先の日 あのつま香をもとめむ 色白い梅（むめ）ども 岡松のあひのき 咲きければ

回文的な作品

回文的音楽

交響曲47番第3楽章の最初と最後

蟹行カノンは、音譜を前から読んだものと後ろから読んだものとを同時に演奏するものである。J.S.バッハの「音楽の捧げもの」にその例がある。

ハイドンの交響曲47番『パリンドローム』の第3楽章は、逆から呼んでも同じ楽譜になる。

回文的な文章

ダグラス・ホフスタッターはそれにちなんで著書『ゲーデル、エッシャー、バッハ』の中で回文的な会話からなる作品を作っている。亀とアキレスの会話が続き、途中で蟹がひと喋りして出て行くが、その後の会話が前半のアキレスと亀の立場を変えて逆にたどるように構成されている。

回文的な和歌・俳句

幕末の仙台に一千句以上の回文的な和歌・俳諧を創作した廻文師・仙代庵（細屋勘左衛門・1796年-1869年）がいる。

• わが身かも長閑かな門の最上川（わかみかものとかなかとのもかみかわ）
• 題目よどんどこどんとよく燃いた（たいもくよとんとことんとよくもいた）
• 長し短かししかし短かな（なかしみしかししかしみしかな）
• みな草の名は百と知れ、薬なり、すぐれし徳は花の作並（みなくさのなははくとしれくすりなりすくれしとくははなのさくなみ）
• 頼むぞのいかにも二階のぞむのだ（たのむそのいかにもにかいのそむのた）
• 嵯峨の名は宿りたりとや花の笠（さかのなはやとりたりとやはなのかさ）
• はかなの世しばしよしばし世の中は（はかなのよしはしよしはしよのなかは）

生物学における“回文”

分子生物学でも回文またはパリンドロームという用語を用いる。これはDNAまたはRNAの配列に関して、二重鎖の一方を読んだ場合と、もう一方（相補鎖）を逆向きに読んだ場合が同じになる構造をいう。制限酵素で切られるターゲット配列はたいてい小規模の回文構造である。また大規模な回文構造はヘアピン状の立体構造をとりうるが、これは遺伝子の調節配列などに多くの例がみられる。

回文を題材にした作品

書籍

• 『土屋耕一回文集—軽い機敏な仔猫何匹いるか—』 土屋耕一（誠文堂新光社 1971年）
• 『つつみがみっつ』 土屋耕一（福音館書店こどものとも 1975年）
• 『笑いの氾濫 巷に息吹く洒落精神』 乙田東洋司（関西市民書房 1981年）
• 『笑学強加書―ことばあそびばらいえてい』 日本笑学指導院笑鬼会本院冗皇・乙田東洋司（社会思想社 1984年）
• 『ことばあそび新文―ユーモア&クレージーニューズ』 笑鬼会本院・乙田東洋司（社会思想社 1986年）
• 『にわのわに』多田ヒロシ（こぐま社 1985年）
• 『まさかさかさま 動物回文集』 石津ちひろ（河出書房新社 1989年）
• 『またたび浴びたタマ』 村上春樹（文藝春秋 2000年）
• 『回文の国へようこそ』坂崎千春（中公文庫 2003年）
• 『ダンスがすんだ』フジモトマサル（新潮社 2004年）
• 『喜劇悲奇劇』 泡坂妻夫
• 『喜劇ひく悲奇劇』 鯨統一郎
• 『ゲームの国（リリおばさんの事件簿1）』 森博嗣
• 『終わりは始まり』 中村航・フジモトマサル（集英社 2008年）
• 『いつも心に好奇心！』 はやみねかおる・松原秀行（講談社 2000年）
• 『みんなでグルグル回文あそび』全三巻 ながたみかこ（汐文社 2008年）
• 『めざせ！回文の達人』 ながたみかこ（大泉書店 2007年）
• 『アニマルマニア』 ながたみかこ（講談社 2003年）

雑誌・番組内のコーナー

• 『笑いの文化人講座』
• 『ターン鳥チキン』 田中れいな・久住小春 （「ハロー!モーニング。」内コーナー: 2005年11月27日～2006年4月9日）
• 『おもしろ回文集「野茂のものは野茂のもの」』 （斉藤洋美のラジオはアメリカン）
• 『ジュニアエラ』回文ちゃれんじ道場
• 『弘兼憲史の回文塾』（週刊ポスト）

楽曲

• 『回文 21 面相』作詞：ビーンズ豆田、作曲：鈴木由花、歌：山崎清介（フジテレビ『ひらけ!ポンキッキ』より）
• 『ん?バナナのななばん』作詞：里乃塚玲央、作曲：大森俊之　（NHK『うたっておどろんぱ』より）
• 『トマト』作詞：荘司武、作曲：大中恩：トマトが回文になっていることをあつかった歌。
• 『こたつたこ』作詞・作曲：内野真澄　（NHK『ピタゴラスイッチ』より）
• 『世迷い言』作詞：阿久悠、作曲：中島みゆき
• 『恋の呪文はスキトキメキトキス』作詞：康珍化、作曲：小林泉美、歌：伊藤さやか（フジテレビ『さすがの猿飛』オープニングテーマ）

コマーシャル

• 山本山のコマーシャル：山本山が漢字の配列で回文になっている点を取り上げている。

キャラクター

• キリンリキ ポケットモンスター
• サルサルサ ライブオン
• トンマノマントタイムパトロール隊オタスケマン
• 山田真耶（やまだまや） インフィニット・ストラトス
• 西尾維新：読みをローマ字表記にしたときに回文になる。
• ABBA：一つ目のBはあえて左右逆に表示されている。

脚注

関連項目

• 回文数
• 12月21日（回文の日）
• アナグラム
• 山内あゆ（色気を含んだ回文作りを得意とするアナウンサー）
• レム色（自作回文のお笑い芸人）
• 土屋耕一 （「軽い機敏な子猫何匹いるか」など回文集の著作があるコピーライター）
• ながたみかこ（「アニマルマニア」「回文ゲーム」他、回文集の著作がある作家）

外部リンク

• 中村航・フジモトマサル回文連載「終わりは始まりII」（集英社WEB文芸レンザブロー）

• ヒマラヤ山系の回文のページ
• 世界最長回文（日本語、かな1197文字。清濁区別なし）
• 非魔神流こじつけ回文（日本語、かな1339文字。清濁区別あり）
• 回文ユンブイカ（日本語、かな1551文字。清濁区別あり）
• 日本一長い回文（日本語、かな3733文字。清濁区別なし）
• A 17,259 word Palindrome（英語、17259語）
• THE LONGEST ONE（ポーランド語、33000字以上）
• 回文21面相（回文ポータルサイト）

wiki en

[Wiki en表示]

"Palindromes" redirects here. For the film, see Palindromes (film).

A palindrome is a word, phrase, number, or other sequence of symbols or elements, whose meaning may be interpreted the same way in either forward or reverse direction.

Composing literature in palindromes is an example of constrained writing. The word "palindrome" was coined from the Greek roots palin (πάλιν; "again") and dromos (δρóμος; "way, direction") by the English writer Ben Jonson in the 17th century. The Greek phrase to describe the phenomenon is karkinikê epigrafê (καρκινικὴ επιγραφή; "crab inscription"), or simply karkinoi (καρκίνοι; "crabs"), alluding to the movement of crabs, such as an inscription that may be read backwards.

History

The Sator Square.

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 works 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 ways: horizontally or vertically from either top left to bottom right or bottom right to top left. As such, they can be referred to as palindromatic.

A palindrome with the same property is the Hebrew palindrome, "We explained the glutton who is in the honey was burned and incinerated", (פרשנו רעבתן שבדבש נתבער ונשרף; PRShNW R`BTN ShBDBSh NTB`R WNShRP or parasnu ra`abhtan shebad'vash nitba'er venisraf), by Abraham ibn Ezra, referring to the halachic question as to whether a fly landing in honey makes the honey treif (non-kosher).

פ ר ש נ ו
ר ע ב ת ן
ש ב ד ב ש
נ ת ב ע ר
ו נ ש ר ף

Another Latin palindrome, "In girum imus nocte et consumimur igni" ("We go wandering at night and are consumed by fire", in which "In girum ire" is translated as "go wandering" instead of the literal "go in a circle", cf. Italian "andare in giro", "go strolling or wandering around"), was said to describe the behavior of moths. It is likely that this palindrome is from medieval rather than ancient times.

Byzantine Greeks often inscribed the palindrome, "Wash [the] sins, not only [the] face" ΝΙΨΟΝ ΑΝΟΜΗΜΑΤΑ ΜΗ ΜΟΝΑΝ ΟΨΙΝ ("Nīpson anomēmata mē mōnan ōpsin", engraving "ps" with the single Greek letter Ψ, psi), on baptismal fonts. This practice was continued in many English churches. Examples include the font at St. Mary's Church, Nottingham and also the font in the basilica of St. Sophia, Constantinople, the font of St. Stephen d'Egres, Paris; at St. Menin's Abbey, Orléans; at Dulwich College; and at the following churches: Worlingworth (Suffolk), Harlow (Essex), Knapton (Norfolk), St Martin, Ludgate (London), and Hadleigh (Suffolk).

Palindromes in The Quran

1 - And Magnify your Lord (Mudathir 74:3)

ر ب ك ف ك ب ر → ﻭرﺑﻚ ﻓﻜﺒﺮ  

Wa Rabbaka Fa Kabbir.

Focus only on the consonants in the Arabic language: R, B, K, f, K, B, R. And your Lord magnify (so magnify your Lord).

2 - They all float -each- in an Orbit. (Yasin 36:40)

ك ﻝ ف ﻱ ف ﻝ ك → ﻭﻛﻞ ﻓﻲ ﻓﻟﻚ ﻳﺴﺒﺤﻮﻥ  

Wa Kullun Fi Falakin Yasbahoon.

K, L, F, y, F, L, K.

See the letters Orbitting/floating around the letter ‘Ya’. In this verse God (Allah) is speaking about how the sun and the moon are in orbit. Notice the letters in red, brown and green. They are all floating around the letter in orange. The next word begins with the letter 'Ya' (of Yasbah, in singular form), which is referring to floating (Tasbeeh is from the same root). The letters are floating around one another, since the concept being discussed is orbit.

Palindromes in ancient Sanskrit

Palindromes of considerable complexity were experimented with in Sanskrit poetry. Complex palindromes appear in the 19th canto of the 8th-century epic poem Śiśupāla-vadha by Magha. It yields the same text if read forward, backward, down, up, or diagonally:

sa-	ka-	ra-	na-	na-	ra-	ka-	sa-
kā-	ya-	sā-	da-	da-	sā-	ya-	kā
ra-	sā-	ha-	vā	vā-	ha-	sā-	ra-
nā-	da-	vā-	da-	da-	vā-	da-	nā.
(nā	da	vā	da	da	vā	da	nā
ra	sā	ha	vā	vā	ha	sā	ra
kā	ya	sā	da	da	sā	ya	kā
sa	kā	ra	nā	nā	ra	kā	sa)

(Note: a hyphen indicates a continuation of same word.) The last four lines are an inversion of the first four and are not part of the verse. They are included here only so that its properties may be more easily discerned, as the up-and-down reading depends on re-reading the text back up again in each column.

The stanza translates as:

[That army], which relished battle (rasāhavā), contained allies who brought low the bodes and gaits of their various striving enemies (sakāranānārakāsakāyasādadasāyakā), and in it the cries of the best of mounts contended with musical instruments (vāhasāranādavādadavādanā).

The same work (Śiśupāla-vadha) also contains stanzas in which each line is a palindrome, and stanzas that may be read backward to give a new stanza (semordnilaps). Such stanzas are also found in the earlier work Kirātārjunīya.

This Sanskrit poem was written by "nandi-ghanta kavis" in kanda style.

सारस नयना घन जघ

नारचित रतार कलिक हर सार रसा

सार रसारह कलिकर

तारत चिरनाघ जनघ नायनसरसा |

Palindromes in Tamil poetry

Palindromes are referred to in Tamil as "Maalai Maatru" (மாலை மாற்று). The earliest known palindromic verses (11 couplets) occur in the devotional poetry of the Shaivism saint Sambandhar who lived around the 7th Century C.E.

The first of these eleven verses runs thus:

யாமாமாநீ யாமாமா யாழீகாமா காணாகா

காணாகாமா காழீயா மாமாயாநீ மாமாயா

It refers to Shiva as the incomparable God, the one who plays the Veena, the beautiful one adorned with snakes, the one who destroyed Kama, whose abode is Sirkazhi, who also appears as Vishnu, and beseeches him (Shiva) to rid the devotee of impurities.

Palindromic verses are also to be found in Madhava Shivagnana Yogi's Kanchi Puranam (மாதவச்சிவஞானயோகிகள் காஞ்சிப் புராணம்) and in Mahavidvaan Meenakshi Sundaram Pillai's Thirunaagaik Kaaronap Puranam (மகாவித்துவான் மீனாட்சிசுந்தரம் பிள்ளை திருநாகைக் காரோணப் புராணம்).

Types

Character, word, or line unit

The most familiar palindromes, in English at least, are character-by-character: The written characters read the same backward as forward. Some examples of common palindromic words: civic, radar, level, rotor, kayak, reviver, racecar, redder, madam, malayalam, and refer. There are also palindromes where the unit of reversal is the word ("So patient a doctor to doctor a patient so") or line (as in the poem "Doppelganger" by J.A. Lindon). These are referred to as "word-unit palindromes" and "line-unit palindromes" respectively. Word-unit palindromes were popularized in the recreational linguistics community by J.A. Lindon in the 1960s, but occasional examples in English are found from at least the 19th century, and several in French and Latin date to the Middle Ages.

Phrases

Palindromes often consist of a phrase or sentence, e.g.: "Eva, can I stab bats in a cave?", "Mr. Owl ate my metal worm", "Was it a car or a cat I saw?", "A nut for a jar of tuna", "Do geese see God?", "Ma is as selfless as I am", "On a clover, if alive erupts a vast pure evil, a fire volcano." "Dammit, I'm mad!", "A Toyota's a Toyota", "Go hang a salami, I'm a lasagna hog", and "A Santa lived as a devil at NASA". Punctuation, capitalization, and spacing are usually ignored, although some, such as "Rats live on no evil star" and "Step on no pets", include the spacing.

Famous English palindromes

Some well-known English palindromes are, "Able was I ere I saw Elba", "A man, a plan, a canal - Panama!", "Madam, I'm Adam" or "Madam in Eden, I'm Adam", "Doc, note: I dissent. A fast never prevents a fatness. I diet on cod" and "Never odd or even". "Rise to vote, sir" was featured in an episode of The Simpsons.

Names

Some people have names that are palindromes. Included are given names (Ada, Anna, Bob, Aviva), surnames (Harrah, Renner, Salas) or both (Eve, Hannah, Maham, Otto). Lon Nol (1913–1985) was Prime Minister of Cambodia. Nisio Isin is a Japanese novelist and manga writer, whose real name (西尾 維新, Nishio Ishin) is a palindrome when romanized using the Kunrei-shiki or the Nihon-shiki systems. (It is often written as NisiOisiN to emphasize this). Some persons have changed their name in order to make of it a palindrome (one example is actor Robert Trebor), while others were given a palindromic name at birth (such as the philologist Revilo P. Oliver).

Palindromic names are very common in Finland. Examples include Olavi Valo, Emma Lamme, Sanna Rannas, Anni Linna and Asko Oksa.

There are also palindromic names in fictional media. "Stanley Yelnats" is the name of a character in Holes, a 1998 novel and 2003 film. Four of the fictional Pokémon species have palindromic names in English (Eevee, Girafarig, Ho-Oh, and Alomomola).

Molecular biology

Main article: Palindromic sequence

Restriction enzymes recognize a specific sequence of nucleotides and produce a double-stranded cut in the DNA. While recognition sequences vary widely, with lengths of between 4 and 8 nucleotides, many of them are palindromic, which correspond to nitrogenous base sequences between complementary strands, which, when read from the 5' to 3' direction, are identical sequences.

Numbers

Main article: Palindromic number

A palindromic number is a number whose digits, with decimal representation usually assumed, are the same read backward, for example, 5885. They are studied in recreational mathematics where palindromic numbers with special properties are sought. A palindromic prime is a palindromic number that is a prime number, for example, 191 and 313.

The continued fraction of is a repeating palindrome when is an integer.

Acoustics

A palindrome in which a recorded phrase of speech sounds the same when it is played backward was discovered by composer John Oswald in 1974 while he was working on audio tape versions of the cut-up technique using recorded readings by William S. Burroughs. Oswald discovered in repeated instances of Burroughs speaking the phrase "I got" that the recordings still sound like "I got" when played backward.

In France, a more complex example has been identified with^{[citation needed]} "Une slave valse nue" (a Slavic girl waltzes naked).

Music

A song called "Bob" had been written by "Weird Al" Yankovic for his album Poodle Hat which the lyrics consists none other than Palindromes.

Classical music

Joseph Haydn's Symphony No. 47 in G is nicknamed "the Palindrome". The third movement, minuet and trio is a musical palindrome. The second half of the piece is the same as the first but backwards.

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, and most famously Béla Bartók. George Crumb also used musical palindrome to text paint the Federico García Lorca poem "¿Por qué nací?", the first movement of three in his fourth book of Madrigals. Igor Stravinsky's final composition, The Owl and the Pussy Cat, is a palindrome.^{[citation needed]}

The first movement from Constant Lambert's ballet Horoscope (1938) is entitled "Palindromic Prelude". Lambert claimed that the theme was dictated to him by the ghost of Bernard van Dieren, who had died in 1936.

British composer Robert Simpson also composed music in the palindrome or based on palindromic themes; the slow movement of his Symphony No. 2 is a palindrome, as is the slow movement of his String Quartet No. 1. His hour-long String Quartet No. 9 consists of thirty-two variations and a fugue on a palindromic theme of Haydn (from the minuet of his Symphony No. 47). All of Simpson's thirty-two variations are themselves palindromic.

The music of Anton Webern is often palindromic. Webern, who had studied the music of the Renaissance composer Heinrich Isaac, was extremely interested in symmetries in music, be they horizontal or vertical. An example of horizontal or linear symmetry in Webern's music is the first phrase in the second movement of the symphony, Op. 21. A striking example of vertical symmetry is the second movement of the Piano Variations, Op. 27, in which Webern arranges every pitch of this dodecaphonic work around the central pitch axis of A4. From this, each downward reaching interval is replicated exactly in the opposite direction. For example, a G♯3—13 half-steps down from A4 is replicated as a B♭5—13 half-steps above.

Just as the letters of a verbal palindrome are not reversed, so are the elements of a musical palindrome usually presented in the same form in both halves. Although these elements are usually single notes, palindromes may be made using more complex elements. For example, Karlheinz Stockhausen's composition Mixtur, originally written in 1964, consists of twenty sections, called "moments", which may be permuted in several different ways, including retrograde presentation, and two versions may be made in a single program. When the composer revised the work in 2003, he prescribed such a palindromic performance, with the twenty moments first played in a "forwards" version, and then "backwards". Each moment, however, is a complex musical unit, and is played in the same direction in each half of the program. By contrast, Karel Goeyvaerts's 1953 electronic composition, Nummer 5 (met zuivere tonen) is an exact palindrome: not only does each event in the second half of the piece occur according to an axis of symmetry at the centre of the work, but each event itself is reversed, so that the note attacks in the first half become note decays in the second, and vice-versa. It is a perfect example of Goeyvaerts's aesthetics, the perfect example of the imperfection of perfection.

In classical music, a crab canon is a canon in which one line of the melody is reversed in time and pitch from the other. A large-scale musical palindrome covering more than one movement is called "chiasic", referring to the cross-shaped Greek letter "χ" (pronounced /ˈkaɪ/.) This is usually a form of reference to the crucifixion; for example, the Crucifixus movement of Bach's Mass in B minor. The purpose of such palindromic balancing is to focus the listener on the central movement, much as one would focus on the center of the cross in the crucifixion. Other examples are found in Bach's cantata BWV 4, Christ lag in Todesbanden, Handel's Messiah and the Fauré Requiem.

A table canon is a rectangular piece of sheet music intended to be played by two musicians facing each other across a table with the music between them, with one musician viewing the music upside down compared to the other. The result is somewhat like two speakers simultaneously reading the Sator square from opposite sides, except that it is typically in two-part polyphony rather than in unison.

Popular music

Musical content

Hüsker Dü's concept album Zen Arcade contains the songs, "Reoccurring Dreams" and "Dreams Reoccurring", the latter of which appears earlier on the album, but is actually the intro of the former song played in reverse. In a similar manner, The Stone Roses' first album contains the songs "Waterfall" and "Don't Stop", the latter of which is, in essence, the former performed backward. The 12" and CD formats of their single Elephant Stone feature the B-side "Full Fathom Five", which is an alternate mix of the title track played in reverse.

The title track of the 1992 album entitled UFO Tofu by Béla Fleck and the Flecktones is said by its composer to be a musical palindrome.

In 2003, the city of San Diego, California commissioned sculptor Roman DeSalvo and composer Joseph Waters to create a public artwork in the form of a safety railing on the 25th Street overpass at F and 25th Streets. The result, Crab Carillon, is a set of 488 tuned chimes that may be played by pedestrians as they cross the overpass. Each chime is tuned to the note of a melody, composed by Waters. The melody is in the form of a palindrome, to accommodate walking in either direction.

The strings part in "Starálfur", from the album Ágætis byrjun by Sigur Rós, is a palindrome.

The song "You Can Call Me Al" by Paul Simon features a palindromic bass run performed by Bakithi Kumalo.

Lyrics

The song, "I Palindrome I", by They Might Be Giants, features palindromic lyrics and imagery. The 27-word bridge is word-symmetrical.

"Weird Al" Yankovic's song, "Bob", from his 2003 album Poodle Hat, consists of rhyming palindromes and is a style parody the Bob Dylan song "Subterranean Homesick Blues". There is an accompanying video for the song which also parodies Dylan's video. Yankovic shows all of the palindromes on cue cards as they are being sung.

Baby Gramps is known for songs where the lyrics are made up of palindromes.

Names and titles

In 1975, the Swedish pop group ABBA had a hit single entitled, "SOS", a unique occasion in which a song's title and the name of its recording artist are both palindromes.

The Grateful Dead's 1969 album Aoxomoxoa is a notable early use of a palindrome in the title of a popular music album.

In 1992, the grunge band Soundgarden released an EP called Satanoscillatemymetallicsonatas or SOMMS; the title is a palindrome and puns on the supposed connection between the Devil and heavy metal music.

On Boris and Sunn O)))'s collaborative album "Altar", the vinyl version included a full disc, double-sided bonus track entitled "Satan Oscillate My Metallic Sonatas" (in reference to the Soundgarden EP of the same name), in which the various instruments (mainly guitars) are introduced one at a time on side one, and then fade out in reverse order on side two. Kim Thayil of Soundgarden appears on this track.

The Fall of Troy made a song with the famous palindrome "A Man, A Plan, A Canal, Panama" as the title.

The first and last tracks on Andrew Bird's album Noble Beast form a palindrome ("Oh No" and "On Ho!") and the seventh track is a palindrome in itself: "Ouo". He has also mentioned palindromes in earlier music, giving his songs names such as "11:11", "T'N'T", and "Fake Palindromes" (although the last title is not a palindrome itself). He also mentions palindromes in the lyrics of the song "I" and the "I" redux "Imitosis".

"racEcar" by Vitamin Party features a repeating chorus of "A Man, A Plan, A Canal, Panama" (the title itself is palindromic).

"Never Odd or Even", which was to be the title of the first album by Aleka's Attic, the band formed by the late River Phoenix, is a palindrome.

"If I Had a Hi-Fi", a 2010 cover album by American alternative rock band Nada Surf, is a palindrome.

Miles Davis and Black Sabbath both had albums called Live Evil. Inversely, Lynch Mob and Diamond Head had albums called Evil Live.

D.R.U.G.S. has two songs that are palindromes on the self-titled debut album, "Mr. Owl Ate My Metal Worm" and "Laminated E.T. Animal".

The Asian-American teenage Riot Grrrl band Emily's Sassy Lime's name is palindromic.

In 2012, the American band Liars released an LP called WIXIW.

The German electronic trio To Rococo Rot is also a palindrome.

Comics

Watchmen #5, "Fearful Symmetry", the first page mirrors the last (in terms of frame disposition), with the following pages mirroring each other before the center-spread is (broadly) symmetrical in layout.

"NogegoN", Volume 3 of Les Terres creuses, by Luc et François Schuiten, Les Humanoïdes Associés, (1990) : each frame has its mirror image.

Television

Disney's Phineas and Ferb frequently alludes to palendromes, including the once-mentioned character Professor Ross E. Forp. Danville, the setting locale is also said to have a "Palendrome Road".

Long palindromes

The longest palindromic word in the Oxford English Dictionary is the onomatopoeic tattarrattat, coined by James Joyce in Ulysses (1922) for a knock on the door. The Guinness Book of Records gives the title to detartrated, the preterite and past participle of detartrate, a chemical term meaning to remove tartrates. Rotavator, a trademarked name for an agricultural machine, is often listed in dictionaries. The term redivider is used by some writers, but appears to be an invented or derived term—only redivide and redivision appear in the Shorter Oxford Dictionary. Malayalam, an Indian language, is of equal length.

In English, two palindromic novels have been published: Satire: Veritas by David Stephens (1980, 58,795 letters), and Dr Awkward & Olson in Oslo by Lawrence Levine (1986, 31,954 words). In French, Oulipo writer George Perec's "Grand Palindrome" (1969) is 5,556 letters in length. In Hebrew, Noam Dovev wrote a 717-word, 2,662 letter palindromic story called, "Name sold, I'd lose man".

Biological structures

Main article: Palindromic sequence

Palindrome of DNA structure

A: Palindrome, B: Loop, C: Stem

In most genomes or sets of genetic instructions, palindromic motifs are found. The meaning of palindrome in the context of genetics is slightly different, however, from the definition used for words and sentences. Since the DNA is formed by two paired strands of nucleotides, and the nucleotides always pair in the same way (Adenine (A) with Thymine (T), Cytosine (C) with Guanine (G)), a (single-stranded) sequence of DNA is said to be a palindrome if it is equal to its complementary sequence read backward. For example, the sequence ACCTAGGT is palindromic because its complement is TGGATCCA, which is equal to the original sequence in reverse complement.

A palindromic DNA sequence may form a hairpin. Palindromic motifs are made by the order of the nucleotides that specify the complex chemicals (proteins) that, 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.^{[citation needed]} A palindrome structure allows the Y-chromosome to repair itself by bending over at the middle if one side is damaged.

It is believed that palindromes frequently are also found in proteins, but their role in the protein function is not clearly known. It has recently been suggested that the prevalence existence of palindromes in peptides might be related to the prevalence of low-complexity regions in proteins, as palindromes frequently are associated with low-complexity sequences. Their prevalence might also be related to an alpha helical formation propensity of these sequences, or in formation of proteins/protein complexes.

Computation theory

In the automata theory, a set of all palindromes in a given alphabet is a typical example of a language that is context-free, but not regular. This means that it is, in theory, impossible for a computer with a finite amount of memory to reliably test for palindromes. (For practical purposes with modern computers, this limitation would apply only to incredibly long letter-sequences.)

In addition, the set of palindromes may not be reliably tested by a deterministic pushdown automaton which also means that they are not LR(k)-parsable or LL(k)-parsable. When reading a palindrome from left-to-right, it is, in essence, impossible to locate the "middle" until the entire word has been read completely.

It is possible to find the longest palindromic substring of a given input string in linear time.

The palindromic density of an infinite word w over an alphabet A is defined to be zero if only finitely many prefixes are palindromes; otherwise, letting the palindromic prefixes be of lengths n_k for k=1,2,... we define the density to be

Among aperiodic words, the largest possible palindromic density is achieved by the Fibonacci word, which has density 1/φ, where φ is the Golden ratio.

A palstar is a composition of palindromic strings.

Semordnilap

Semordnilap is a name coined for a word or phrase that spells a different word or phrase backward. "semordnilap" is itself "palindromes" spelled backward. According to logologist Dmitri A. Borgmann, the word was coined by Martin Gardner in Oddities and Curiosities of Words and Literature. Semordnilaps are also known as volvograms, heteropalindromes, semi-palindromes, half-palindromes, reversgrams, mynoretehs, reversible anagrams, word reversals, or anadromes. They have also sometimes been called antigrams, though now, this term usually refers to anagrams with opposing meanings.

These words are very useful in constructing palindromic texts; together, each pair forms a palindrome, and they may be added on either side of a shorter palindrome in order to extend it.

The longest single-word English examples contain eight letters, such as "stressed" ("desserts") and "dioramas" ("samaroid", resembling a samara). Other shorter examples include "deliver" ("reviled") and "swap" ("paws").

Non-English palindromes

According to Guinness World Records, the Finnish word saippuakivikauppias (soapstone vendor), a 19-letter word, is claimed to be the world's longest palindromic word in everyday use. A meaningful derivative from it is saippuakalasalakauppias (soapfish bootlegger). An even longer effort is saippuakuppinippukauppias (soap dish wholesale vendor). Almost equally long is the Estonian word kuulilennuteetunneliluuk (the hatch a bullet flies out of when exiting a tunnel).

The longest palindrome in the Dutch language, according to the Dutch Guinness Book of World Records, is koortsmeetsysteemstrook, which translates into English as thermometer (for measuring fevers).

See also

• Ambigram
• Anagram
• Antimetabole
• Backmasking
• Constrained writing
• List of palindromic places
• Palindromic number
• Palindromic polynomial
• Pangram
• Phonetic palindrome
• Su Hui (poet)
• Yreka, California for the palindromic Yreka Bakery and Yrella Gallery

References

External links

• List of palindromes from Princeton Lexical Database.

English Journal

• A perfect palindrome in the Escherichia coli chromosome forms DNA hairpins on both leading- and lagging-strands.

• Azeroglu B1, Lincker F1, White MA1, Jain D1, Leach DR2.
• Nucleic acids research.Nucleic Acids Res.2014 Nov 11. pii: gku1136. [Epub ahead of print]
• DNA palindromes are hotspots for DNA double strand breaks, inverted duplications and intra-chromosomal translocations in a wide spectrum of organisms from bacteria to humans. These reactions are mediated by DNA secondary structures such as hairpins and cruciforms. In order to further investigate the
• PMID 25389268

• Utility of indels for species-level identification of a biologically complex plant group: a study with intergenic spacer in Citrus.

• Mahadani P1, Ghosh SK.
• Molecular biology reports.Mol Biol Rep.2014 Nov;41(11):7217-22. doi: 10.1007/s11033-014-3606-7. Epub 2014 Jul 22.
• The Consortium of Barcode of Life plant working group proposed to use the defined portion of plastid genes rbcL and matK either singly or in combination as the standard DNA barcode for plants. But DNA barcode based identification of biologically complex plant groups are always a challenging task due
• PMID 25048292

• Next Generation Sequencing Identifies a Novel Rearrangement in the HBB Cluster Permitting to-the-Base Characterization.

• Shooter C1, Rooks H, Thein SL, Clark B.
• Human mutation.Hum Mutat.2014 Oct 21. doi: 10.1002/humu.22707. [Epub ahead of print]
• Genetic testing for hemoglobinopathies is required for prenatal diagnosis, understanding complex cases where multiple pathogenic variants may be present or investigating cases of unexplained anemia. Characterization of disease causing variants that range from single base changes to large rearrangeme
• PMID 25331561

Japanese Journal

• 回文発句資料考 : 野々口立圃筆回文短冊紹介

• 小野 恭靖
• 大阪教育大学紀要. 第Ⅰ部門, 人文科学 = Memoirs of Osaka Kyoiku University 62(1), 51-55, 2013-09
• … The oblong card in which he wrote the first phrase of the haikai using the palindrome remains now. …
• NAID 120005342910

• 回文にみる漢字文化的思考

• 朱 捷
• 総合文化研究所紀要 29, 93-108, 2012
• NAID 40019427474

• 人工DNA結合タンパク質のデザインと細胞機能制御への展開

• 今西 未来
• YAKUGAKU ZASSHI 132(12), 1431-1436, 2012
• … The motif is attractive for designing artificial transcription factors with desired DNA binding specificities because of its characteristic DNA binding properties: (1) recognition of 3 bp per motif, (2) tandemly connected modular structure, and (3) binding to non-palindrome sequences as a monomer. …
• NAID 130002489524

Related Links

• Palindrome - Wikipedia, the free encyclopedia

A palindrome is a word, phrase, number, or other sequence of units that may be read the same way in either direction, with general allowances for adjustments to punctuation and word dividers. Composing literature in palindromes is an ...

• Palindromes

Palindromes Web Site. ... Palindromes are words or phrases that read the same in both directions, e.g. EYE,or RACECAR, or MADAM I'M ADAM. ... We've divided our favourite palindromes and palindrome articles into these categories: ...

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