Double backslash on last line of matrix










8














Is \ necessary on the final line of environments like matrix, align, and gather? For example, with amsmath,



[beginbmatrix
3 & 1\
2 & 4\
endbmatrix]


and



[beginbmatrix
3 & 1\
2 & 4
endbmatrix]


seem to produce the same output. But are they really the same? Is one preferable to the other, or is it a matter of taste? From my understanding, \ in one of these environments is used to separate lines, and there's nothing else to separate the final line from, so it's not necessary.










share|improve this question























  • If it produces the same output, I guess there's no difference.
    – Tvde1
    Nov 12 '18 at 14:11










  • I think there's no rule for this. I think it depends on the implementation of the environment. With align, for instance, you get an undesired line if you add the \ at the end.
    – Phelype Oleinik
    Nov 12 '18 at 14:16















8














Is \ necessary on the final line of environments like matrix, align, and gather? For example, with amsmath,



[beginbmatrix
3 & 1\
2 & 4\
endbmatrix]


and



[beginbmatrix
3 & 1\
2 & 4
endbmatrix]


seem to produce the same output. But are they really the same? Is one preferable to the other, or is it a matter of taste? From my understanding, \ in one of these environments is used to separate lines, and there's nothing else to separate the final line from, so it's not necessary.










share|improve this question























  • If it produces the same output, I guess there's no difference.
    – Tvde1
    Nov 12 '18 at 14:11










  • I think there's no rule for this. I think it depends on the implementation of the environment. With align, for instance, you get an undesired line if you add the \ at the end.
    – Phelype Oleinik
    Nov 12 '18 at 14:16













8












8








8







Is \ necessary on the final line of environments like matrix, align, and gather? For example, with amsmath,



[beginbmatrix
3 & 1\
2 & 4\
endbmatrix]


and



[beginbmatrix
3 & 1\
2 & 4
endbmatrix]


seem to produce the same output. But are they really the same? Is one preferable to the other, or is it a matter of taste? From my understanding, \ in one of these environments is used to separate lines, and there's nothing else to separate the final line from, so it's not necessary.










share|improve this question















Is \ necessary on the final line of environments like matrix, align, and gather? For example, with amsmath,



[beginbmatrix
3 & 1\
2 & 4\
endbmatrix]


and



[beginbmatrix
3 & 1\
2 & 4
endbmatrix]


seem to produce the same output. But are they really the same? Is one preferable to the other, or is it a matter of taste? From my understanding, \ in one of these environments is used to separate lines, and there's nothing else to separate the final line from, so it's not necessary.







matrices






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edited Nov 12 '18 at 14:11

























asked Nov 12 '18 at 14:07









MathIsFun

675




675











  • If it produces the same output, I guess there's no difference.
    – Tvde1
    Nov 12 '18 at 14:11










  • I think there's no rule for this. I think it depends on the implementation of the environment. With align, for instance, you get an undesired line if you add the \ at the end.
    – Phelype Oleinik
    Nov 12 '18 at 14:16
















  • If it produces the same output, I guess there's no difference.
    – Tvde1
    Nov 12 '18 at 14:11










  • I think there's no rule for this. I think it depends on the implementation of the environment. With align, for instance, you get an undesired line if you add the \ at the end.
    – Phelype Oleinik
    Nov 12 '18 at 14:16















If it produces the same output, I guess there's no difference.
– Tvde1
Nov 12 '18 at 14:11




If it produces the same output, I guess there's no difference.
– Tvde1
Nov 12 '18 at 14:11












I think there's no rule for this. I think it depends on the implementation of the environment. With align, for instance, you get an undesired line if you add the \ at the end.
– Phelype Oleinik
Nov 12 '18 at 14:16




I think there's no rule for this. I think it depends on the implementation of the environment. With align, for instance, you get an undesired line if you add the \ at the end.
– Phelype Oleinik
Nov 12 '18 at 14:16










1 Answer
1






active

oldest

votes


















7














There is no difference at all for bmatrix. There is for align.



Any array or tabular allows a trailing \; it is obviously mandatory if hline is needed at the bottom, but otherwise omitting it is safe.



Since Xmatrix (where X stands for noting, p, b, B, v or V) is array in disguise, the same applies. Also cases falls in this class.



It's very different with align, alignat, xalignat, flalign and gather (or *-forms thereof), where a trailing \ would produce a new empty row (with the equation number in the case of no *), so it must be avoided.



As a habit, I tend to avoid the trailing \ in Xmatrix, just for symmetry with the alignment environments mentioned above.






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    1 Answer
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    active

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    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    7














    There is no difference at all for bmatrix. There is for align.



    Any array or tabular allows a trailing \; it is obviously mandatory if hline is needed at the bottom, but otherwise omitting it is safe.



    Since Xmatrix (where X stands for noting, p, b, B, v or V) is array in disguise, the same applies. Also cases falls in this class.



    It's very different with align, alignat, xalignat, flalign and gather (or *-forms thereof), where a trailing \ would produce a new empty row (with the equation number in the case of no *), so it must be avoided.



    As a habit, I tend to avoid the trailing \ in Xmatrix, just for symmetry with the alignment environments mentioned above.






    share|improve this answer

























      7














      There is no difference at all for bmatrix. There is for align.



      Any array or tabular allows a trailing \; it is obviously mandatory if hline is needed at the bottom, but otherwise omitting it is safe.



      Since Xmatrix (where X stands for noting, p, b, B, v or V) is array in disguise, the same applies. Also cases falls in this class.



      It's very different with align, alignat, xalignat, flalign and gather (or *-forms thereof), where a trailing \ would produce a new empty row (with the equation number in the case of no *), so it must be avoided.



      As a habit, I tend to avoid the trailing \ in Xmatrix, just for symmetry with the alignment environments mentioned above.






      share|improve this answer























        7












        7








        7






        There is no difference at all for bmatrix. There is for align.



        Any array or tabular allows a trailing \; it is obviously mandatory if hline is needed at the bottom, but otherwise omitting it is safe.



        Since Xmatrix (where X stands for noting, p, b, B, v or V) is array in disguise, the same applies. Also cases falls in this class.



        It's very different with align, alignat, xalignat, flalign and gather (or *-forms thereof), where a trailing \ would produce a new empty row (with the equation number in the case of no *), so it must be avoided.



        As a habit, I tend to avoid the trailing \ in Xmatrix, just for symmetry with the alignment environments mentioned above.






        share|improve this answer












        There is no difference at all for bmatrix. There is for align.



        Any array or tabular allows a trailing \; it is obviously mandatory if hline is needed at the bottom, but otherwise omitting it is safe.



        Since Xmatrix (where X stands for noting, p, b, B, v or V) is array in disguise, the same applies. Also cases falls in this class.



        It's very different with align, alignat, xalignat, flalign and gather (or *-forms thereof), where a trailing \ would produce a new empty row (with the equation number in the case of no *), so it must be avoided.



        As a habit, I tend to avoid the trailing \ in Xmatrix, just for symmetry with the alignment environments mentioned above.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered Nov 12 '18 at 14:29









        egreg

        709k8618823165




        709k8618823165



























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