我有一个环境中的三个节点的内容aligned。为什么它是右对齐的？我&在第一行的第一个字符之前有。
\documentclass[10pt]{amsart}
\usepackage{amssymb}
\usepackage{mathtools,array}
\usepackage{tikz}
\usetikzlibrary{calc,intersections,arrows.meta,bending}
\usepackage{pgfplots}
\pgfplotsset{compat=1.11}
\setlength{\oddsidemargin}{0.0in}
\setlength{\evensidemargin}{0.0in} \setlength{\textwidth}{6.1in}
\setlength{\topmargin}{0.0in} \setlength{\textheight}{9in}
\begin{document}
\noindent \hspace*{\fill}
\begin{tikzpicture}[nodes={inner sep=0, font=\scriptsize,
execute at begin node={\setlength\abovedisplayskip{0.75ex}%
\setlength\belowdisplayskip{0.5ex}%
\setlength\abovedisplayshortskip{0.75ex}%
\setlength\belowdisplayshortskip{0.5ex}}},
shorten/.style={shorten >=#1,shorten <=#1},
pics/fpic/.style={code={#1}}, x=1.5cm, y=1.5cm]
%A sequence of graphs is drawn, starting with the vertex with the b-label b.
\matrix[row sep=4.5em]{%<--- This defines the difference between pictures.
%Here is the blow-up of the vertex labeled b.
\pic{fpic={%
\draw[fill] (-4,0) circle (1.5pt);
\node[anchor=north] (label_for_Vertex_b) at ($(-4,0) +(0,-0.25)$){\textit{b}};
\node[anchor=south] at ($(-4,0) +(0,0.25)$){$\dfrac{0}{1}$};
}};\\
%
%
\pic{fpic={%
\draw (-4,0) -- (-2,0) coordinate(lcompare);
\draw[fill] (-4,0) circle (1.5pt);
\draw[fill] (-2,0) circle (1.5pt);
%
\node[anchor=north] (bcompare) at ($(-4,0) +(0,-0.25)$){\textit{b}};
\node[anchor=south] (label_for_Farey_Fraction_at_Vertex_b) at ($(-4,0) +(0,0.25)$){$\dfrac{0}{1}$};
%
\node[anchor=north] (label_for_Vertex_b-1) at ($(-2,0) +(0,-0.25)$){$b - 1$};
\node[anchor=south] at ($(-2,0) +(0,0.25)$){$\dfrac{1}{1}$};
%
%A "pin" is drawn between the midpoint of the first edge and its label.
\coordinate (label_for_first_Edge) at (-3,0);
\draw[draw=gray, line width=0.8pt, shorten <=1mm, shorten >=1mm] (-3,-0.5) -- (label_for_first_Edge);
\node[anchor=north, align=center, inner sep=0, font=\scriptsize] at (-3,-0.5){$\begin{aligned}&2\bigl[b+(b-1)\bigr] \\[-1ex]
&\qquad=2^{2}b-2
\end{aligned}$};
}}; \\
%
%
\pic{fpic={%
%Here is the blow-up of the vertex labeled b-1.
\draw (-4,0) -- (-2,0) -- (0,0);
\draw[fill] (-4,0) circle (1.5pt);
\draw[fill] (-2,0) circle (1.5pt);
\draw[fill] (0,0) circle (1.5pt);
%
\node[anchor=north] at ($(-4,0) +(0,-0.25)$){\textit{b}};
\node[anchor=south] at ($(-4,0) +(0,0.25)$){$\dfrac{0}{1}$};
%
\node[anchor=north] at ($(-2,0) +(0,-0.25)$){$b - 1$};
\node[anchor=south] (label_for_Farey_Fraction_at_Vertex_b-1) at ($(-2,0) +(0,0.25)$){$\dfrac{1}{1}$};
%
\node[anchor=north] (label_for_Vertex_b-2) at ($(0,0) +(0,-0.25)$){$b - 2$};
\node[anchor=south] at ($(0,0) +(0,0.25)$){$\dfrac{2}{1}$};
%
\node[anchor=north] at ($(-3,0) +(0,-0.1)$){$2^{2}b - 2$};
\node[anchor=north] at ($(-1,0) +(0,-0.1)$){$2^{2}b - 6$};
}}; \\
%
%
\pic{fpic={
%Here is the blow-up of the vertex labeled b-n.
\draw (-4,0) -- (-2,0) -- (0,0) (2,0) -- (5,0);
\draw[fill] (-4,0) circle (1.5pt);
\draw[fill] (-2,0) circle (1.5pt);
\draw[fill] (0,0) circle (1.5pt);
\node (first_ellipses) at (1,0){$\ldots$};
\coordinate (tail_for_bent_arrow_below_first_ellipses) at ($(first_ellipses) +(0,-0.25)$);
\draw[fill] (2,0) circle (1.5pt);
\draw[fill] (5,0) circle (1.5pt);
%
\node[anchor=north] at ($(-4,0) +(0,-0.25)$){\textit{b}};
\node[anchor=south] at ($(-4,0) +(0,0.25)$){$\dfrac{0}{1}$};
%
\node[anchor=north] at ($(-2,0) +(0,-0.25)$){$b-1$};
\node[anchor=south] at ($(-2,0) +(0,0.25)$){$\dfrac{1}{1}$};
%
\node[anchor=north] at ($(0,0) +(0,-0.25)$){$b-2$};
\node[anchor=south] at ($(0,0) +(0,0.25)$){$\dfrac{2}{1}$};
%
\node[anchor=south] (label_for_phantom_Farey_Fraction_at_ellipses) at ($(1,0) +(0,0.25)$){\hphantom{$\dfrac{1}{1}$}};
\coordinate (point_just_above_node_containing_phantom_Farey_Fraction) at ($(label_for_phantom_Farey_Fraction_at_ellipses.north) +(0,0.1)$);
%
\node[anchor=north] at ($(2,0) +(0,-0.25)$){$b-n$};
\node[anchor=south] at ($(2,0) +(0,0.25)$){$\dfrac{n}{1}$};
%
\node[anchor=north] at ($(5,0) +(0,-0.25)$){$b-(n+1)$};
\node[anchor=south] at ($(5,0) +(0,0.25)$){$\dfrac{n+1}{1}$};
%
%
%
%
%A dashed arrow is drawn to the midpoint of the edge between last two vertices.
\draw[-latex, dashed, line width=0.8pt, shorten <=3mm, shorten >=1mm, overlay] ($(3.5,0) +(60:1.625)$) -- (3.5,0);
\path node[anchor=south, align=center, text width={width("future vertex")}, overlay] at ($(3.5,0) +(60:1.625)$)
{future mediant\\for vertex\[\dfrac{2n+1}{2}\]};
%
%A "pin" is drawn between the midpoint of the last edge and its label.
\coordinate (label_for_Edge) at ($(3.5,-0.5) +(0,-0.75)$);
\draw[draw=gray, line width=0.8pt, shorten <=1mm, shorten >=1mm] (3.5,0) -- (label_for_Edge);
\node[anchor=north, align=center, inner sep=0, font=\scriptsize] (edge label) at (label_for_Edge){$\begin{aligned}&\text{Present edge label of} \\[-1ex]
&\quad2\bigl[(b-n)+\bigl(b-(n+1)\bigr)\bigr] \\[-1ex]
&\qquad=2^{2}b-2(2n+1)
\end{aligned}$};
}}; \\
\pic{fpic={
%Here is the vertex placed at the broken edge.
\draw (-4,0) -- (-2,0) -- (0,0) (2,0) -- (5,0);
\draw[fill] (-4,0) circle (1.5pt);
\draw[fill] (-2,0) circle (1.5pt);
\draw[fill] (0,0) circle (1.5pt);
\node (second_ellipses) at (1,0){$\ldots$};
\coordinate (head_for_bent_arrow_above_second_ellipses) at ($(second_ellipses) +(0,0.75)$);
\draw[fill] (2,0) circle (1.5pt);
\draw[fill] ({(2+5)/2},0) circle (1.5pt);
\draw[fill] (5,0) circle (1.5pt);
%
\node[anchor=north] at ($(-4,0) +(0,-0.25)$){\textit{b}};
\node[anchor=south] at ($(-4,0) +(0,0.25)$){$\dfrac{0}{1}$};
%
\node[anchor=north] at ($(-2,0) +(0,-0.25)$){$b - 1$};
\node[anchor=south] at ($(-2,0) +(0,0.25)$){$\dfrac{1}{1}$};
%
\node[anchor=north] at ($(0,0) +(0,-0.25)$){$b-2$};
\node[anchor=south] at ($(0,0) +(0,0.25)$){$\dfrac{2}{1}$};
%
\node[anchor=north] at ($(2,0) +(0,-0.25)$){$b-n$};
\node[anchor=south] at ($(2,0) +(0,0.25)$){$\dfrac{n}{1}$};
%
\node[anchor=north] at ($(5,0) +(0,-0.25)$){$b-(n+1)$};
\node[anchor=south] at ($(5,0) +(0,0.25)$){$\dfrac{n+1}{1}$};
%
%A "pin" is drawn between the midpoint of the last edge and its label.
\draw[draw=gray, line width=0.8pt, shorten <=1mm, shorten >=1mm] ({(2+5)/2},0) -- ({(2+5)/2},-0.75);
\node[anchor=north] at ({(2+5)/2},-0.75){$2^{2}b-(2n+1)2$};
\node[anchor=south] (f2n) at ($({(2+5)/2},0) +(0,0.25)$){$\dfrac{2n+1}{2}$};
%
\draw[draw=gray, line width=0.8pt, shorten <=1mm, shorten >=1mm] ({(3*2+5)/4},0) -- ({(3*2+5)/4-0.75*sqrt(2)},{-0.75*sqrt(2)});
\node[anchor=north east, align=center, inner sep=0, font=\scriptsize] at ({(3*2+5)/4-0.75*sqrt(2)},{-0.75*sqrt(2)})
{$\begin{aligned}&2\bigl[(b-n)+\bigl(2^{2}b-(2n+1)\bigr)2\bigr] - \bigl(b-(n+1)\bigr) \\[-1ex]
&=3^{2}b-3(3n+1)
\end{aligned}$};
\draw[draw=gray, line width=0.8pt, shorten <=1mm, shorten >=1mm] ({(2+3*5)/4},0) -- ({(2+3*5)/4+ (1.5)*1/2},{(1.5)* (-sqrt(3)/2)});
\node[anchor=north, align=center, inner sep=0, font=\scriptsize] at ({(2+3*5)/4+ (1.5)*1/2},{(1.5)* (-sqrt(3)/2)})
{$\begin{aligned}&2\bigl[\bigl(b-(n+1)\bigr)+\bigl(2^{2}b-(2n+1)\bigr)2\bigr] - (b-n) \\[-1ex]
&=3^{2}b-3(3n+2)
\end{aligned}$};
}}; \\
};
%
%
%
%
%Arrows are drawn between the diagrams.
\draw[-latex, line width=0.8pt, shorten=7.5pt] (label_for_Vertex_b) to[bend right=30] node[midway, right=1.5mm, align=center]
{Blow-up of\\vertex \textit{b}} (label_for_Farey_Fraction_at_Vertex_b);
%
\draw[-latex, line width=0.8pt, shorten=7.5pt] (label_for_Vertex_b-1) to[bend right=30] node[midway, right=1.5mm, align=center]
{Blow-up of\\vertex $b - 1$} (label_for_Farey_Fraction_at_Vertex_b-1);
%
\draw[-latex, line width=0.8pt, shorten=7.5pt] (label_for_Vertex_b-2) to[bend right=30] node[pos=1/3, right=1.5mm, align=center]
{Blow-up of more\\\hphantom{\ }vertices} (point_just_above_node_containing_phantom_Farey_Fraction);
%
\draw[-latex, line width=0.8pt, shorten <=7.5pt, shorten >=7.5pt] (tail_for_bent_arrow_below_first_ellipses) to[bend right=30]
(head_for_bent_arrow_above_second_ellipses);
%
%
\node[draw, text width=0.25\linewidth,inner sep=2mm,align=left, below left=5mm] at (current bounding box.north east)
{In each step of the expanding simple graphs,
the vertices are labeled with a fraction and
an \textit{b}-label. The fraction is a Farey
Fraction; it is typeset above each vertex.};
\end{tikzpicture}
\hspace{\fill}
\end{document}