-T+ e1 Eq e2:bool <= T+ e1:t & T+ e2:t
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-If e1 and e2 are of the same type, then Eq or NEq return bool
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-[Plus, Minus, Times, Div]
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-T+ e1 Plus e2:int <= T+ e1:int & T+ e2:int
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-The operators Plus/Minus/Times/Div return int if both operands are ints
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-[Lt, ELt, Gt, EGt]
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-T+ e1 Lt e2:bool <= T+ e1:int & T+ e2:int
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-The operators Lt/ELt/Gt/EGt return bool if both operands are ints
+<e1 o e2,c> => <v,c''> <= <e1,c> => <v1,c'> <e2,c'> => <v2,c''> v is the result of using operator o on v1 and v2