An underline-based shorthand

Introduction

This page describes a simple shorthand I have developed. It is based on underlining and double-underlining some letters of the word. It was inspired by LZ77 and LZ88 (see Wikipedia).

Note that your browser may not show single and double underline correctly with some letters: e.g. Jj, Jj and Jj should all look distinct.

How it works

To repeat two or more letters immediately, underline them with a single underline. The repeated letters are highlighted in the decoded text like this:

To specify a nonzero distance between the underlined letters and where they should be repeated, double underline one or more of the underlined letters. The maximum distance is length×(length+1)/2 where length is the number of letters to repeat:

There may be multiple replacements in a single word. The replacements may overlap, in which case they must be evaluated from left to right. Underlined and inserted substrings only count as one unit of distance:

Limitations:

• Two underlined parts may not be next to each other because they would be indistinguishable from a single long underlined part. E.g. ABABCDCD cannot be shortened into ABCD because that would mean ABCDABCD.
• The underlined letters cannot be repeated more than once.

Examples of English words

I found the words in Linux by using the grep command on the file /usr/share/dict/words.

One repeated substring

• 5 letters:
  • nationalis = nationalisation
  • rationalis = rationalisation
  • whippersna = whippersnappers
• 4 letters:
  • abracad = abracadabra
  • atherosclis = atherosclerosis
  • bandst = bandstands
  • beri = beriberi
  • flibbertigt = flibbertigibbet
  • grandst = grandstands
  • handst = handstands
  • hodgep = hodgepodge
  • hots = hotshots
  • lightwe = lightweight
  • priestl = priestliest
  • underfd = underfunded
• 3 letters:
  • backp = backpack
  • barian = barbarian
  • conted = contented
  • mur = murmur
  • nonse = nonsense
  • posses / posses = possesses
  • racetk = racetrack
  • senti = sentient
  • undergro = underground

Two repeated substrings

• Non-overlapping:
  • foredaing = foreordaining
  • inseitivy = insensitivity
  • nondeminatiol = nondenominational
  • phosrescen = phosphorescence
  • postmiress = postmistresses
  • proietress = proprietresses
  • relentssne = relentlessness
  • senlessn = senselessness
  • sheprdess = shepherdesses
  • sleepssne = sleeplessness
• Overlapping:
  • crisso = crisscross
  • ingrati (double underlined “g”) = ingratiating
  • knicka = knickknack
  • waster = wastewater