I got a help on drawing this diagram from here



        & P \ar[dl, dashed, "\tilde{f}" ']
        \ar[d, "f"]     \\
        A \ar[r,twoheadrightarrow,"g" ']   & B  \arrow[r, twoheadrightarrow] & 0

But how can I split the arrow as shown below:

?enter image description here

2 Answers 2


enter image description here

That is your third very similar question ... so I estimate that it is time, that you read documentation for the tikz-cdpackage and make yourself more familiar with this package ;-). You need to insert new row between existed:

Edit: Considered is @campa's comment:

\documentclass[border=3mm, varwidth]{standalone}

        & F(S)\mathrlap{{}= P\oplus K} \ar[ddl, dashed, "\tilde{f}" ']
                            \ar[d,"\pi"]    \\
        & P \ar[d,"F'"]     \\  % <---
M \ar[r,"\varphi" ']   & B  \ar[r] & 0
  • 1
    +1 but may I suggest F(S) \mathrlap{{}= P\oplus K} (with mathtools) instead of the \hspace? In this way no guessing is needed and the left "triangle" isn't as wide.
    – campa
    Commented Feb 15, 2021 at 12:17
  • 1
    @campa, good idea. Thank you very much!. Considered in edited answer!
    – Zarko
    Commented Feb 15, 2021 at 12:21
  • Ok I promise I will thank you!@Zarko
    – Smart20
    Commented Feb 15, 2021 at 14:07

Peraphs in origin the commutative-diagrams is done with xy package and the fonts of mtpro2.

PS: Excuse me very much @egreg for the tips that you not like. :-(


& **[r] \pazocal{F}(S)= P\oplus K \ar[d]^\pi \ar@{-->}[ddl]_{F'} & \\
& B \ar[d]^{f} &  \\ 
M \ar[r]^{\varphi} & N\ar[r]& 0

enter image description here

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