Xjyuk

I'd like to typset the tree on the left of the image. Unfortunately, TikZ seems way to complicated to me... I tried with this code, without success

documentclassbeamer
usepackagetikz % Game theory packages
usetikzlibrarycalc

% Node styles
tikzset
% Two node styles for game trees: solid and hollow
solid node/.style=circle,draw,inner sep=1.5,fill=black,
hollow node/.style=circle,draw,inner sep=1.5


begindocument

beginframe
 begintikzpicture[scale=0.7,font=footnotesize]
 % Specify spacing for each level of the tree
 tikzstylelevel 1=[level distance=18mm,sibling distance=27mm]
 tikzstylelevel 2=[level distance=18mm,sibling distance=27mm]
 % The Tree
 node(0)[hollow node,label=above:$1$]
 childnode(1)[solid node, label=above:$2$]
 childnode(0-1-1)[solid node, label=above:$1$] edge from parent node[left]$E$
 childnode(0-1-2)[label=below:$(3,1)$] edge from parent node[right]$F$ 
 childnode(0-1-1-1)[label=below:$(1,2)$] edge from parent node[right]$G$ % The error is here
 edge from parent node[left,xshift=-3]$C$ 
 
 childnode(2)[label=below:$(0,3)$] edge from parent node[right, xshift=3]$D$
 ;

 endtikzpicture
endframe
enddocument

I'd like also to ask you if something easier for game theory than Tikz exists for trees.

Note that there is a package, istgame, which specializes on game trees. For general trees, forest is a very powerful tool. It allows you to draw your tree very easily.

documentclassarticle
usepackageforest
forestsetel/.style=edge label=node [pos=0.7,above,outer sep=3pt] $#1$ 
begindocument
beginforest
for tree=circle,fill,inner sep=1pt,calign=fixed edge angles
[,label=above:1
 [,label=above left:2,el=A
 [,label=above left:1,el=C
 [,label=below:0,2,el=E ]
 [,label=below:2,0,el=F ]
 ]
 [,label=below:1,1,el=D]
 ]
 [,label=below:3,3,el=B]
]
endforest
enddocument

I propose this short code with pstricks – more specifically pst-tree:

documentclassarticle
usepackage[utf8]inputenc
usepackage[T1]fontenc
usepackagefourier
usepackagepst-tree
usepackageauto-pst-pdf

begindocument

beginpspicture
pssettnsep=1pt, labelsep=3pt
pstree[nodesep=0pt, levelsep=1.5cm, treesep=3cm]Tc2pt~[ tnpos=a, tnsep=-1pt]1 
 pstreeTdotnbput$ A $ uput[ul](pssucc)$ 2 $ %
 pstreeTdot nbput$ C $ uput[ul](pssucc)1%
 pstreeTdot nbput$ E $ uput[ul](pssucc)2%
 Tdotnaput$F$uput[d](pssucc)$0,2$%
 Tdot_$D$ uput[d](pssucc)$1,1$%
Tdot_$B$ uput[d](pssucc)$3,3$
 endpspicture%

 enddocument

My plain TikZ code is a bit long but easy to read.

documentclassarticle
%documentclassbeamer
usepackagetikz
begindocument
%beginframe 
begincenter
begintikzpicture[scale=1,
h/.style=circle,draw=magenta,thick,inner sep=1.5,
s/.style=h,fill=magenta]
path
(0,0) node[h] (1) node[above] 1 
+(1,-1) node[s] (2b) node[below] 3,3
++(-1,-1) node[s] (2a) node[left] 2 
+(1,-1) node[s] (3b) node[below] 1,1
++(-1,-1) node[s] (3a) node[left] 1 
+(1,-1) node[s] (4b) node[below] 0,2
+(-1,-1) node[s] (4a) node[below] 2,0;

draw (1)
--(2a) node[pos=.4,left]A
--(3a) node[pos=.4,left]C
--(4a) node[pos=.4,left]E
(1)--(2b) node[pos=.4,right]B
(2a)--(3b) node[pos=.4,right]D
(3a)--(4b) node[pos=.4,right]F;

newcommandputcolumn[6]%
path #1 node#2 
++(-90:1) node#3 ++(-90:1) node#4
++(-90:1) node#5 ++(-90:1) node#6;
%
beginscope[shift=(4,0)]
draw (0,0) grid (2,-4);
putcolumn(.5,.5)C2,00,23,33,3
putcolumn(1.5,.5)D1,11,13,33,3
putcolumn(-.5,.5)AEAFBEBF
endscope
endtikzpicture
endcenter
%endframe 
enddocument