Prove:
(Proposition (commutativity of addition): + = ) ,
under the assumptions:
(Definition (addition): 1) ,
(Definition (addition): 2) .
As there are several methods which can be applied, we have different choices to proceed with the proof.
Alternative proof 1: failed
The proof of ()fails. (The prover "Simplifier" was unable to transform the proof situation.)
Alternative proof 2: failed
We try to prove () by induction on .
Induction Base:
(1) .
As there are several methods which can be applied, we have different choices to proceed with the proof.
Alternative proof 1: proved
We take in () all variables arbitrary but fixed:
(4)
and simplify it.
Simplification of the lhs term:
⌋
Simplification of the rhs term:
= by ()
⌋
Hence, it is sufficient to prove:
(5) .
We prove () by induction on .
Induction Base:
(6) .
A proof by simplification of () works.
Simplification of the lhs term:
= by ()
⌋
Simplification of the rhs term:
⌋
Induction Step:
Induction Hypothesis:
(7)
Induction Conclusion:
(8) .
A proof by simplification of () works.
Simplification of the lhs term:
= by ()
= by ()
⌋
Simplification of the rhs term:
⌋
Alternative proof 2: pending
Pending proof of ().
Induction Step:
Induction Hypothesis:
(2)
Induction Conclusion:
(3) .
As there are several methods which can be applied, we have different choices to proceed with the proof.
Alternative proof 1: failed
We take in () all variables arbitrary but fixed:
(9)
and simplify it.
Simplification of the lhs term:
⌋
Simplification of the rhs term:
= by ()
⌋
Hence, it is sufficient to prove:
(10) .
We try to prove () by induction on .
Induction Base:
(11) .
We simplify ().
Simplification of the lhs term:
= by ()
⌋
Simplification of the rhs term:
⌋
Hence, it is sufficient to prove:
(14) .
The proof of () fails. (No applicable inference rule was found.)
Induction Step:
Induction Hypothesis:
(12)
Induction Conclusion:
(13) .
We simplify ().
Simplification of the lhs term:
= by ()
= by ()
⌋
Simplification of the rhs term:
⌋
Hence, it is sufficient to prove:
(15) .
The proof of () fails. (No applicable inference rule was found.)
Alternative proof 2: failed
We try to prove () by induction on .
Induction Base:
(16) .
We simplify ().
Simplification of the lhs term:
= by ()
⌋
Simplification of the rhs term:
= by ()
⌋
Hence, it is sufficient to prove:
(19) .
The proof of () fails. (No applicable inference rule was found.)
Induction Step:
Induction Hypothesis:
(17)
Induction Conclusion:
(18) .
Pending proof of ().
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