Dual

Dual may refer to:

Dual! Parallel Trouble Adventure

Dual! Parallel Trouble Adventure (デュアル!ぱられルンルン物語, Dyuaru! Parare Runrun Monogatari) is a fourteen episode series created in 1999 by Masaki Kajishima and produced by AIC, both well known for the Tenchi Muyo! franchise. It is licensed in the US by Pioneer LDC, later known as Geneon. In addition to the original run, an OVA special was added to conclude the series as a de facto "14th episode".

Title explanation

The title refers to the fact that the story takes place in two parallel universes, a concept loosely based on multiverse theory.

Plot

22 years ago, a huge alien artifact is found on a construction site by a worker named Yotsuga. The foreman orders that the artifact be broken apart to avoid delays. As Yotsuga walks towards the dumpsters to dispose of a small piece of the artifact, the world splits into two. In one world, Yotsuga tosses away the piece and the artifact is destroyed. In the other world, Yotsuga keeps the artifact, leading to the discovery of extraterrestrial technology that changes history.

Dual (grammatical number)

Dual (abbreviated DU) is a grammatical number that some languages use in addition to singular and plural. When a noun or pronoun appears in dual form, it is interpreted as referring to precisely two of the entities (objects or persons) identified by the noun or pronoun. Verbs can also have dual agreement forms in these languages.

The dual number existed in Proto-Indo-European, persisted in many of the now extinct ancient Indo-European languages that descended from it such as Ancient Greek and Gothic and can still be found in a few modern Indo-European languages such as Scottish Gaelic, Slovenian, and Sorbian. Among surviving ancient languages, Sanskrit uses dual forms across nouns, verbs, and adjectives. Many more modern Indo-European languages show residual traces of the dual, as in the English distinctions both vs. all, either vs. any, neither vs. none, and so on.

Many Semitic languages also have dual number. For instance, in Arabic, ان -ān, is added to the end of any noun to indicate that it is dual (regardless of how the plural is being formed).