Proof: Write Stmt Tab Unchanged Expr33

Let's prove the following theorem:

if the following are true:
  • the line at time 33 = 3
  • the tab at time 33 = 2
  • statement at line 3, tab 2 = self."first_name" = first_name
  • expression state at time 33 = "end_expr"

then the tab at time 34 = 2

Proof:

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Given
1 the line at time 33 = 3
2 the tab at time 33 = 2
3 statement at line 3, tab 2 = self."first_name" = first_name
4 expression state at time 33 = "end_expr"
Proof Table
# Claim Reason
1 the tab at time (33 + 1) = the tab at time 33 if the line at time 33 = 3 and the tab at time 33 = 2 and statement at line 3, tab 2 = self."first_name" = first_name and expression state at time 33 = "end_expr", then the tab at time (33 + 1) = the tab at time 33
2 the tab at time (33 + 1) = 2 if the tab at time (33 + 1) = the tab at time 33 and the tab at time 33 = 2, then the tab at time (33 + 1) = 2
3 33 + 1 = 34 33 + 1 = 34
4 the tab at time (33 + 1) = the tab at time 34 if 33 + 1 = 34, then the tab at time (33 + 1) = the tab at time 34
5 the tab at time 34 = 2 if the tab at time (33 + 1) = the tab at time 34 and the tab at time (33 + 1) = 2, then the tab at time 34 = 2

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