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When I first visited this page I thought my browser was not capable of displaying the symbol. I eventually figured out that the symbol really is a featureless empty square. I wonder if anyone can suggest a way to make this more obvious. I know it says "the four sides of the box representing..." in
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This bothered me as well. I was hoping that - by analogy with the greek capital delta - there existed some D'Alembertian character with one or two bolded edges, however I could not find one in use or in any of the common LaTeX sets. Whilst a greek-ish D'Alembertian character has been proposed at
1103:
I also agree. When I first saw it I was uncertain if it was a symbol or error. Put the text caveat right under the equation or in a similarly obvious spot. Each section needs a caveat because many people don't read the whole article - they skip right to the section they are interested in.
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I agree, I saw this operator on another page and followed the link to see what it "should" look like. Maybe add some bold text at the start of the article to let those of us who are "too familiar" with computers know that the square box isn't a browser bug!
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1369:{\displaystyle \Box ={\frac {1}{c^{2}}}{\frac {\partial ^{2}}{\partial t^{2}}}-{\frac {\partial ^{2}}{\partial x^{2}}}-{\frac {\partial ^{2}}{\partial y^{2}}}-{\frac {\partial ^{2}}{\partial z^{2}}}}
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I seem to recall this is also
Griffiths's definition, although not Jackson's. The answer is that there is no answer, but we can at least try to be consistent within wikipedia. --
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I've rewritten the article to only mention all alternate notation, but only use the Delta-symbol for the
Laplacian which the d'Alembertian is. Comments welcome. --
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My notes (3rd year undergrad course on
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is simply the
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This may be obvious, but I've had a devil of a time confirming it... The D'Alembert
Operator is named for
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articles are using the convention where the minus sign goes on the time parts, so then it would be
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on
Knowledge. If you would like to participate, please visit the project page, where you can join
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use that notation. Currently the notation section does not mention this, so I will add it in --
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823:{\displaystyle \Box ^{2}={\frac {1}{c^{2}}}{\frac {\partial ^{2}}{\partial t^{2}}}\nabla ^{2}}
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969:, correct? Seems like that should be mentioned somewhere if it is (as I assume it to) true.--
513:{\displaystyle \Delta :=(\mathrm {d} +\mathrm {d} ^{*})^{2}=|_{\mathbf {R} ^{3}}-\nabla ^{2}}
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416:{\displaystyle {\frac {1}{c^{2}}}{\frac {\partial ^{2}}{\partial t^{2}}}-\nabla ^{2}}
340:{\displaystyle \nabla ^{2}-{\frac {1}{c^{2}}}{\frac {\partial ^{2}}{\partial t^{2}}}}
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in
Minkowski space. Some precision or clarification on that issue would be helpful.
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I think it should definitely be mentioned that the operator is often written as
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D^2 + m or D^2 - m is a matter of convention, because the sign of D^2 is. --
737:{\displaystyle \Box ={\frac {1}{c}}{\frac {\partial }{\partial t}}-\nabla }
830:. It goes on to remark that some texts refer to the d'Alembertian as
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I note that some pages have a tag warning readers of this issue:
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Something is amiss. I found a website claiming that although
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This is correct. I have added a link to the eponymous fellow.
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and this warning is still often necessary (see examples at
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The article has a single reference and the link is dead
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261:{\displaystyle \Box =\partial _{t}^{2}-\nabla _{x}^{2}}
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1177:{\displaystyle \partial ^{\mu }}
1150:{\displaystyle \partial _{\mu }}
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109:and see a list of open tasks.
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906:{\displaystyle \Box ^{2}}
870:{\displaystyle \Box ^{2}}
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202:{\displaystyle \Box ^{2}}
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915:MathWorld
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1190:TonyMath
1108:unsigned
1074:Eutactic
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36:scale.
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653:β
643:β
620:β
611:β
584:β»
558:β»
528:β»
502:β
498:β
459:β
438::=
435:Ξ
405:β
401:β
385:β
375:β
322:β
312:β
289:β
280:β
245:β
241:β
227:β
220:β»
209:?
191:β»
170:β»
1531:(
1511:(
1502:c
1493:x
1479:(
1463:1
1460:=
1457:c
1437:)
1434:1
1428:,
1425:1
1419:,
1416:1
1410:,
1407:1
1404:(
1400:g
1397:a
1394:i
1391:d
1387:=
1384:g
1359:2
1355:z
1345:2
1327:2
1323:y
1313:2
1295:2
1291:x
1281:2
1263:2
1259:t
1249:2
1235:2
1231:c
1227:1
1222:=
1205:c
1192:(
1114:(
1093:(
1076:(
1056:(
1023:.
1013:.
983:(
921:(
899:2
863:2
816:2
803:2
799:t
789:2
775:2
771:c
767:1
762:=
757:2
723:t
709:c
706:1
701:=
661:2
657:t
647:2
633:2
629:c
625:1
615:2
562:2
506:2
491:3
486:R
479:|
474:=
469:2
465:)
454:d
449:+
445:d
441:(
409:2
393:2
389:t
379:2
365:2
361:c
357:1
330:2
326:t
316:2
302:2
298:c
294:1
284:2
254:2
249:x
236:2
231:t
223:=
195:2
143:.
42::
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