Other Dimensions of The Discworld - L-space

For the classical F-spaces Lp and spaces, see Lp space

For abstract normed Riesz spaces, see Banach lattice.

L-space, short for library-space, is the ultimate portrayal of Pratchett's concept that the written word has powerful magical properties on the Discworld, and that in large quantities all books warp space and time around them. The principle of L-space revolves around a seemingly logical equation; it is an extension of the aphorism 'Knowledge is Power':

Large quantities of magical and mundane books create portals into L-space that can be accessed using innate powers of librarianship that are taught by the Librarians of Time and Space to those deemed worthy across the multiverse. Because libraries with enough books to open a portal are often large and sprawling, those venturing into L-space may not necessarily know that they have arrived. The floor and ceiling of L-space follow the floor and ceiling of the library used to access it; the best example of this is that the central dome of Unseen University's library is "always overhead". In every direction and as far as the eye can see bookshelves stretch off, meaning the nature of any walls are unknown.

Essentially, all bookstores are potentially infinite in extent; gateways into literary hyperspace: " good bookshop is just a genteel blackhole that knows how to read."

Because L-space links every library, (and also possibly Death's Autobiography Library) it is possible to reach any one of these throughout space, time and the multiverse. This means that there are potentially other forms of data storage other than books as it represents every library anywhere. Additionally, one can read any book ever written, any book that will be written at some point and books that were planned for writing that were not, as well as any book that could possibly be written (note that this does not mean knowledge of everything; how would you distinguish the "correct" books from the "incorrect" ones?). As this is a form of interdimensional and time travel, there are strict limits on its use, and the Librarians of Time and Space, that is those who have access to L-space have developed three simple rules to ensure abuse is kept to a minimum:

1. Silence
2. Books must be returned by the last date stamped
3. Do not interfere with the nature of causality

Senior librarians are also taught how to deal with the dangers of navigating L-space, such as the "harmless kickstool crabs, large and heavy wandering thesauri, the .303 bookworm and the dreaded cliches, which must be avoided at all costs". Adventurers may find markings and scribbled notes on the shelves to help them navigate.

The Librarian moves through L-space back in time to discover when the book on the summoning of noble dragons was stolen and to confirm that it was stolen by the Elucidated Brethren. During his journey he sees himself asleep at his desk and is tempted to communicate, but realises that this would be breaking the third rule and stops himself. He does however leave the library and follow the thief through the streets, demonstrating how L-space can be used for time travel outside of the library itself.

The Librarian joins the wizards in a Lancre adventure to stop elves from ruining the wedding, and ending the lives, of the new royal family, which includes former witch Magrat Garlick. Within this we learn "the thaumic mathematics are complex, but boil down to the fact that all books, everywhere, affect all other books." From there the nature of bi-directionalism is revealed to demonstrate that any book ever to be written can be found in any book not yet written. In mathematical terms, as noted in The Science of Discworld, L-Space represents a form of phase space. This made possible the study of invisible writings.

After Vorbis has ordered the soldiers and Brutha to burn down the Ephebian library, and the flames start to rise higher, there is a paragraph describing how the Librarian appears with a sack, and then describes how several scrolls that were thought to have been destroyed in the great fire appear in the Unseen University Library.

The concept of L-Space is similar to Lucien's library in the Sandman graphic novels of Neil Gaiman and to the Library of Babel of Jorge Luis Borges.

The name L-space is based on use of E-space (Exo-space) and N-space (Normal space) used by Doctor Who.