Structuralism

Structuralism as a term refers to various theories across the humanities, social sciences and economics many of which share the assumption that structural relationships between concepts vary between different cultures/languages and that these relationships can be usefully exposed and explored.
More accurately it could be described as an approach in academic disciplines in general that explores the relationships between fundamental principal elements in language, literature, and other fields upon which some higher mental, linguistic, social, or cultural "structures" and "structural networks" are built. Through these networks meaning is produced within a particular person, system, or culture. This meaning then frames and motivates the actions of individuals and groups. In its most recent manifestation, structuralism as a field of academic interest began around 1958 and peaked in the late 1960s and early 1970s. (Wikipedia)
In literary theory, structuralism is an approach to analyzing the narrative material by examining the underlying invariant structure. For example, a literary critic applying a structuralist literary theory might say that the authors of the West Side Story did not write anything "really" new, because their work has the same structure as Shakespeare's Romeo and Juliet.
In both texts a girl and a boy fall in love (a "formula" with a symbolic operator between them would be "Boy + Girl") despite the fact that they belong to two groups that hate each other ("Boy's Group - Girl's Group" or "Opposing forces") and conflict is resolved by their death.
The versatility of structuralism is such that a literary critic could make the same claim about a story of two friendly families ("Boy's Family + Girl's Family") that arrange a marriage between their children despite the fact that the children hate each other ("Boy - Girl") and then the children commit suicide to escape the arranged marriage; the justification is that the second story's structure is an 'inversion' of the first story's structure: the relationship between the values of love and the two pairs of parties involved have been reversed.
Structuralistic literary criticism argues that the "novelty value of a literary text" can lie only in new structure, rather than in the specifics of character development and voice in which that structure is expressed. One branch of literary structuralism, like Freudianism, Marxism, and transformational grammar, posits both a deep and a surface structure. In Freudianism and Marxism the deep structure is a story, in Freud's case the battle, ultimately, between the life and death instincts, and in Marx, the conflicts between classes that are rooted in the economic "base."
Literary structuralism often follows the lead of Vladimir Propp (Fairtale) and Claude Levi-Strauss (Structure of Myth) in seeking out basic deep elements in stories and myths, which are combined in various ways to produce the many versions of the ur-story or ur-myth. As in Freud and Marx, but in contrast to transformational grammar, these basic elements are meaning-bearing.
There is considerable similarity between structural literary theory and Northrop Frye's archetypal criticism, which is also indebted to the anthropological study of myths. Some critics have also tried to apply the theory to individual works, but the effort to find unique structures in individual literary works runs counter to the structuralist program and has an affinity with New Criticism.
The other branch of literary structuralism is semiotics, and it is based on the work of Ferdinand de Saussure.