# Big Step Semantics Editor

Here is a proof tree editor.

Each line of your tree should have the following components:

- a number followed by a period to indicate its depth in the tree. 0 is the root.
- a configuration, in the form
`<`$stmt$, s$n$`>`(where $n$ is an integer) or as a set of variable assignments. For example, the notation`s2`represents $\sigma_2$. - A downarrow operator as
`||`,`||e`, or`||b`, as appropriate. - A value
- A rule name in parenthesis.

If you use `s` or `s1`, etc. in your proof tree, you must
follow the tree with their expanded out definitions.

The starter code shows a valid tree for a proof of $\lt m := x + 1, \sigma \gt \Downarrow \sigma_2$.

Here are the big step rules.

# Proof Tree Editor

$\frac{\frac{\frac{}{\displaystyle <x,\sigma_{}> \Downarrow_e 3} \textstyle \mathrm{V\small{AR}} \quad \frac{}{\displaystyle <1,\sigma_{}> \Downarrow_e 1} \textstyle \mathrm{C\small{ONST}}}{\displaystyle <x+1,\sigma_{}> \Downarrow_e 10}\textstyle \mathrm{A\small{RITH}}}{\displaystyle <m:=x+y,\sigma_{}> \Downarrow \sigma_{2}}\textstyle \mathrm{A\small{SSIGN}}$