Symbols Challenge from the AMS: Archive

Last updated: 17 November 1998

Questions

This collection will change once a week until our deadline, November 20.

Go to the page with the current selection.
Look at the complete symbols collection.
Please note that the ``reference IDs'' are purely arbitrary, so that we can find things; they should not be used for any other purpose.

The examples here represent ``families'' of symbols. Documentation may address any similar family members, not just the symbols shown.

Questions from October 27:

  1. Does the length of arrows imply a difference in meaning? For example, would a long arrow carrying a notation above or below mean something different than a short arrow of similar shape, or is the extra length required simply for appearance? (This question applies only to in-line and display notation, not to diagrams, which are excluded from this study by request of the UTC.)

    1.  
      E233 2190 E201

    2.  
      21D4 E202

  2. For what symbols does size matter? Unicode recognizes the distinction between ``cumulative'' and ``binary'' versions of these:

      22C2 22C3
      2229 222A
      22C0 22C1
      2227 2228

    Is there a similar distinction for these?

    1.  
      2295 E255

    2.  
      2297 E256

    3.  
      22C8 EC0D

  3. These symbols may have differing meanings; if so, what are they, and in what fields is each form used?

    1.  
      226A E2FB

    2.  
      2271 E2A6 E2A5

    3.  
      224F E316

  4. Inequalities can be combined and embellished nearly without limit. What do these combinations mean, and where are they used?

    1.  
      E315 E2C7

    2.  
      E268 E26B

    3.  
      E325 E329 E31D E31F E321

  5. Is there a difference in meaning between these similar looking symbols with more or fewer elements and differences in the orientation of some of the elements?

    1.  
      22DA E2F9 E32B

    2.  
      22DC E5CF

    3.  
      228A E2B6 E2B9 E2B8

  6. Is there any difference in meaning between a symbol negated by a slash and one negated by a vertical stroke?

    1.  
      21AE E650

    2.  
      226E E2C3

    3.  
      2269 E2A1

    4.  
      2274 E3BE

    5.  
      2288 E2B1

    6. What about a backwards slanting negation stroke?

      E388 E387 E34D

  7. We are looking for concise definitions and examples of usage of some symbols. Can someone provide this information?

    1.  
      E25C E25D

    2.  
      E25E E25F

    3.  
      E339 E33A E33B E33C E33D E33E

    4.  
      E347 E348 E349 E34A

    5.  
      E351 E352 E353 E354

    6.  
      E34B E34C

Skip to the section on submitting documentation.

Questions from November 3:

This group of questions concentrates on arrows and harpoons.
  1. What is the distinction between arrows with ``open'' and ordinary arrowheads – if any?

    1.  
      2190 2192 2194

    2.  
      E242 E241 E243

  2. What is the meaning of the small diamond to which these arrows point, and where would the arrows be used?

    1.  
      E222 E220

    2.  
      E223 E221

  3. Are these curved arrows the same or different? How are they used?
    1.  
      E21C 219D E21B E21D

    2.  
      EA4D 21BA E5A3

    3.  
      21B7 E23E E21A

  4. Where are arrow tails used alone, without heads?

    1.  
      E23A E23C

    2.  
      E23B E23D

  5. Here are some arrows in combination. We need examples and definitions.

    1.  
      EA07 E5A0 E5A1

    2.  
      E21E E21F E5A2 E240

    3.  
      E236 E234 E24D E235

    4.  
      E35E E35F EA64

    5.  
      E33F E340 EA59

  6. We know that these symbols are used in knot theory and braid groups, but we need examples in text and ordinary displays, not in diagrams. Are we missing any?

      ED00 ED01 ED02 ED03
      ED04 ED05 ED06 ED07

  7. Just about anything that arrows can do, so can harpoons.
    1. Each of these can point in four directions: left, right, up, down.

      F507 F508 F509 F50E E225

    2. These seem to be horizontal only (there is a right-pointing counterpart to each of these that points left).

      E22B E22C E22E E231

Skip to the section on submitting documentation.

Questions from November 10:

This week's topic is alphabetics – letters from alphabets with the Latin letter complement and shapes other than roman (lightface or bold) and italic. (The Greek and cyrillic alphabets are adequately covered already.)

Unicode recognizes some ``variant'' alphabetics with fixed meanings, but we believe the rest of these alphabets are also in common use. We would like to convince the UTC to recognize three complete alphabets, and need examples of the letters that are not in Unicode.

The letters shown below are the ones currently in Unicode.

  1. Blackboard bold:
    We would particularly like examples of lowercase letters, Greek letters, and numerals other than 0 and 1.

    2102 210D 2115 2119 211A 211D 2124

  2. Fraktur:

    212D 2107 210C 2111 211C 2128

  3. Script:

    212F 210A 210E 2113 2134
    212C 2130 2131 210B 2110 2112 2133 211B

  4. Unicode also confuses and combines as
    2118
    We should be able to get this corrected with proper documentation.

Skip to the section on submitting documentation.

Questions from November 17:

  1. Fish tails seem to be somewhere between arrows and precedence relations.

    1. Do these
      E214 E215
      mean the same as these?
      22B0 22B1

    2. They can also be vertical.
      E24B E24C

  2. Sometimes otherwise familiar symbols are embellished with dots, circles, hats, . . . Where are these used, and what do they mean?

    1.  
      E38B E314 E38A

    2.  
      E309 E318

    3.  
      E31D E31F E321

    4.  
      E325 E326

    5.  
      E38C

    6.  
      E329 E32A

  3. Some symbols are closed by adding a straight line or arc to an ``open'' angle or curve. What does this mean?

    1.  
      E355 E358

    2.  
      E352 E353

    3.  
      E279 E27A

  4. What do these combinations of symbols mean, and where are they used?

    1.  
      F431 E330 E32F

    2.  
      E281 E374

    3.  
      E270 E271

    4.  
      E272 E36E

How to submit documentation

Information can be sent either by e-mail or on paper (via fax or post).

Please include the following information:

Ideal documentation would consist of a copy of or reference to a single page of a book or paper from an established publisher that shows two or more similarly shaped symbols from our search list in a context where the distinctions in meaning are obvious. Examples requiring several pages are also welcome. A brief definition or description of the meaning(s) for each symbol is also needed.

We must be able to locate these references to make paper copies. (Examples provided to the UTC must be on paper.)

Please send e-mail responses to symbols@ams.org. Photocopies and other paper documentation should be sent to

STIX Symbols Project
Electronic Products and Services
American Mathematical Society
P.O. Box 6248
Providence, RI 02940-6248
U.S.A.
 
Fax:   +1 401 331-3842

Thank you for your assistance in this project.

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