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In one book I came across the notation $A^\dagger := \overline{A}^T$. But how does one usually handwrite it? When I try to do it, it seems so similar to $A^+$

marmistrz
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    It is usually referred to as a "dagger", which is common notation for the "Hermitian Adjoint" of a matrix. Another common notation is $A^*$ – John Martin May 23 '16 at 18:06
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    The notation $A^+$ often would not have any particular meaning, it thus many not be much of a problem. – quid May 23 '16 at 18:14
  • @quid, some literature use it to denote the Moore-Penrose inverse; one could conceivably see a linear algebra paper where conjugate transposition and taking the pseudoinverse of a matrix are both done. (In that case, I would follow Siddharth's first suggestion.) – J. M. ain't a mathematician May 23 '16 at 18:25
  • @J.M. Yes I agree with both. Maybe let us throw some more stuff in the mix like $ L^T L^\perp T^{\dagger}T^+ $. :-) – quid May 23 '16 at 22:24

2 Answers2

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Lots of people use $A^*$ to represent the Conjugate Transpose.

To actually draw the dagger, draw a really long vertical line, dashed with a small horizontal. I personally dash the horizontal at an angle when I'm doing this so I know that it's a dagger.

Picture of different daggers I personally use the third style like I mentioned.

Siddharth Bhat
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Never thought I'd give handwriting advice here, but I suppose this does fall under notation. I agree, the dagger can look like a plus sign. My rendition adds a guard to the dagger's pommel. Additional advantage: it's a single stroke.

Adagger

zahbaz
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