scratch
system:sage

{{{id=5|

///
}}}

{{{id=7|
var('x,y')
implicit_plot(x^2+y^2-3, (x,-1.1,1.1), (y,-1.1,1.1), plot_points=200) + points([])
///

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/wstein/travel/2009/pnw-maa/talk/nb/worksheets/admin/6/code/27.py", line 8, in <module>
    exec compile(ur'implicit_plot(x**_sage_const_2 +y**_sage_const_2 -_sage_const_3 , (x,-_sage_const_1p1 ,_sage_const_1p1 ), (y,-_sage_const_1p1 ,_sage_const_1p1 ), plot_points=_sage_const_200 ) + points([])' + '\n', '', 'single')
  File "/Users/wstein/build/sage-3.4/local/lib/python2.5/site-packages/SQLAlchemy-0.4.6-py2.5.egg/", line 1, in <module>
    
  File "sage_object.pyx", line 98, in sage.structure.sage_object.SageObject.__repr__ (sage/structure/sage_object.c:1085)
  File "/Users/wstein/build/sage-3.4/local/lib/python2.5/site-packages/sage/plot/plot.py", line 861, in _repr_
    self.show()
  File "/Users/wstein/build/sage-3.4/local/lib/python2.5/site-packages/sage/plot/plot.py", line 1286, in show
    hgridlinesstyle=hgridlinesstyle)
  File "/Users/wstein/build/sage-3.4/local/lib/python2.5/site-packages/sage/plot/plot.py", line 1506, in save
    g._render_on_subplot(subplot)
  File "/Users/wstein/build/sage-3.4/local/lib/python2.5/site-packages/sage/plot/point.py", line 110, in _render_on_subplot
    subplot.scatter(self.xdata, self.ydata, s=s, c=c, alpha=a, **scatteroptions)
  File "/Users/wstein/build/sage-3.4/local/lib/python2.5/site-packages/matplotlib/axes.py", line 5225, in scatter
    minx = np.amin(temp_x)
  File "/Users/wstein/build/sage-3.4/local/lib/python2.5/site-packages/numpy/core/fromnumeric.py", line 1525, in amin
    return amin(axis, out)
ValueError: zero-size array to ufunc.reduce without identity
}}}

{{{id=6|

///
}}}

{{{id=0|
Poset([[1,2],[4],[3],[4],[]]).show()
///
}}}

{{{id=3|

///
}}}