Metamath Proof Explorer


Theorem nic-idlem2

Description: Lemma for nic-id . Inference used by nic-id . (Contributed by Jeff Hoffman, 17-Nov-2007) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Hypothesis nic-idlem2.1 ( 𝜂 ⊼ ( ( 𝜑 ⊼ ( 𝜒𝜓 ) ) ⊼ 𝜃 ) )
Assertion nic-idlem2 ( ( 𝜃 ⊼ ( 𝜏 ⊼ ( 𝜏𝜏 ) ) ) ⊼ 𝜂 )

Proof

Step Hyp Ref Expression
1 nic-idlem2.1 ( 𝜂 ⊼ ( ( 𝜑 ⊼ ( 𝜒𝜓 ) ) ⊼ 𝜃 ) )
2 nic-ax ( ( 𝜑 ⊼ ( 𝜒𝜓 ) ) ⊼ ( ( 𝜏 ⊼ ( 𝜏𝜏 ) ) ⊼ ( ( 𝜑𝜒 ) ⊼ ( ( 𝜑𝜑 ) ⊼ ( 𝜑𝜑 ) ) ) ) )
3 2 nic-imp ( ( 𝜃 ⊼ ( 𝜏 ⊼ ( 𝜏𝜏 ) ) ) ⊼ ( ( ( 𝜑 ⊼ ( 𝜒𝜓 ) ) ⊼ 𝜃 ) ⊼ ( ( 𝜑 ⊼ ( 𝜒𝜓 ) ) ⊼ 𝜃 ) ) )
4 3 nic-imp ( ( 𝜂 ⊼ ( ( 𝜑 ⊼ ( 𝜒𝜓 ) ) ⊼ 𝜃 ) ) ⊼ ( ( ( 𝜃 ⊼ ( 𝜏 ⊼ ( 𝜏𝜏 ) ) ) ⊼ 𝜂 ) ⊼ ( ( 𝜃 ⊼ ( 𝜏 ⊼ ( 𝜏𝜏 ) ) ) ⊼ 𝜂 ) ) )
5 1 4 nic-mp ( ( 𝜃 ⊼ ( 𝜏 ⊼ ( 𝜏𝜏 ) ) ) ⊼ 𝜂 )