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CLASSICAL FIRST-ORDER LOGIC WITH EQUALITY
Propositional calculus
Abbreviated conjunction and disjunction of three wff's
3impdir
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3exp1
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Theorem
3impdir
Description:
Importation inference (undistribute conjunction).
(Contributed by
NM
, 20-Aug-1995)
Ref
Expression
Hypothesis
3impdir.1
⊢
φ
∧
ψ
∧
χ
∧
ψ
→
θ
Assertion
3impdir
⊢
φ
∧
χ
∧
ψ
→
θ
Proof
Step
Hyp
Ref
Expression
1
3impdir.1
⊢
φ
∧
ψ
∧
χ
∧
ψ
→
θ
2
1
anandirs
⊢
φ
∧
χ
∧
ψ
→
θ
3
2
3impa
⊢
φ
∧
χ
∧
ψ
→
θ