How to make an arrow between arrows that is not sloped?

Question

I am trying to make a diagram with arrows between arrows.
Here is how it currently looks:

with code:
begin{tikzcd}
& a arrow[ld, "Rei"', no head, ""{name=r1}] arrow[rd, "Rei", no head, ""{name=r2}] &                                
b arrow["Neu"', no head, loop, distance=2em, in=305, out=235] &
& c arrow[d, "PosRes", no head] 
&                                                           & d
& arrow[no head, from=r1, to=r2, dashed]
end{tikzcd}

I would like that dashed line to be straight. It appears to me that this happens because the arrow is "pointing" to the label of the right-most "Rei" arrow. I would like it to point to the center of it, so that the line is straight. However, I cannot find how to do this. Is there a general way to specify that the "arrow between arrows" should point to the center of each arrow (rather than the labels)? If not, what would be a good way to achieve this?

gernot · Accepted Answer

You could specify the to coordinate as the point on the same height as r1, but below r2. Additionally you can use shorten > (and shorten <, if needed) to adjust the length. Something like to=r1-|r2, shorten >=0.5em.

documentclass{article}

usepackage{tikz-cd}

begin{document}
begin{tikzcd}
& a arrow[ld, "Rei"', no head, ""{name=r1}] arrow[rd, "Rei", no head, ""{name=r2}] &                                
b arrow["Neu"', no head, loop, distance=2em, in=305, out=235] &
& c arrow[d, "PosRes", no head] 
&                                                           & d
& arrow[no head, from=r1, to=r1-|r2, dashed,shorten >=0.5em]
end{tikzcd}
end{document}

Zarko · Answer

Almost the same as @gernot answer (+1, he beat me for a minute, but my code is wee bit shorter):
documentclass{standalone}
usepackage{tikz-cd}

begin{document}
    begin{tikzcd}[arrows=-]
    & a arrow[ld, "mathrm{Rei}"', ""{name=r1}] 
        arrow[rd, "mathrm{Rei}" , ""{name=r2}] 
        &                                
b arrow["mathrm{Neu}"', loop, distance=2em, in=305, out=235] 
    &
        & c arrow[d, "mathrm{PosRes}"] 
    &   & d
        & arrow[from=r1, to=r2 |-r1, dashed, shorten >=0.5em]
    end{tikzcd}
end{document}

Sebastiano · Answer

My code it is off-topic with the tag, but also the forgotten xy package can do the same code like tikz-cd. Here there is my MWE:
documentclass[a4paper,12pt]{article}
usepackage{mathtools}
usepackage[all]{xy}
begin{document}
xymatrix@R=3pc@C=4pc{ar @{} [dr] |{hspace{2.1cm} -------}
& a ar@{-}[dl]_{mathrm{Rei}} ar@{-}[dr]^{mathrm{Rei}}& 
b ar@{-}@(dl,dr)_{mathrm{Neu}}& & c ar@{-}[d]^{mathrm{Pos,Res}}
 &  & d
}
end{document}

The line are right...if you make a zoom you get the straight lines.

How to make an arrow between arrows that is not sloped?

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