How can I give shape to some arrow in tikz, to draw the inclusion arrow?
I read a similar question How to typeset inclusion arrow? with given answer, but the answer didn't really used TikZ, which I really need in order to produce nice large diagrams.
For instance, in this diagram (taken from here ), I want, say, A to be included in A' :
\matrix (m) [matrix of math nodes, row sep=3em, column sep=3em]
{ 0 & A & B & C & 0 \\
0 & A' & B' & C' & 0 \\ };
{ [start chain] \chainin (m-1-1);
\chainin (m-1-2);
{ [start branch=A] \chainin (m-2-2)
[join={node[right,labeled] {\eta_1}}];}
\chainin (m-1-3) [join={node[above,labeled] {\varphi}}];
{ [start branch=B] \chainin (m-2-3)
[join={node[right,labeled] {\eta_2}}];}
\chainin (m-1-4) [join={node[above,labeled] {\psi}}];
{ [start branch=C] \chainin (m-2-4)
[join={node[right,labeled] {\eta_3}}];}
\chainin (m-1-5); }
{ [start chain] \chainin (m-2-1);
\chainin (m-2-2);
\chainin (m-2-3) [join={node[above,labeled] {\varphi'}}];
\chainin (m-2-4) [join={node[above,labeled] {\psi'}}];
\chainin (m-2-5); }