diff --git a/specifications/LearnProofs/AddTwo.tla b/specifications/LearnProofs/AddTwo.tla index 74da1464..804204a6 100644 --- a/specifications/LearnProofs/AddTwo.tla +++ b/specifications/LearnProofs/AddTwo.tla @@ -44,16 +44,16 @@ THEOREM TypeInvariant == Spec => []TypeOK a|b == \E c \in Nat : a*c = b -AlwaysEven == 2|x - -THEOREM Spec => []AlwaysEven - <1>a. Init => AlwaysEven - BY DEF Init, AlwaysEven, | - <1>b. AlwaysEven /\ UNCHANGED vars => AlwaysEven' - BY DEF AlwaysEven, vars - <1>c. AlwaysEven /\ Next => AlwaysEven' +Even == 2|x + +THEOREM Spec => []Even + <1>a. Init => Even + BY DEF Init, Even, | + <1>b. Even /\ UNCHANGED vars => Even' + BY DEF Even, vars + <1>c. Even /\ Next => Even' BY \A c \in Nat : c+1 \in Nat /\ 2*(c+1) = 2*c + 2, Zenon - DEF TypeOK, AlwaysEven, Next, | + DEF TypeOK, Even, Next, | <1> QED BY PTL, <1>a, <1>b, <1>c DEF Spec =============================================================================