Metamath Proof Explorer


Theorem syl2an

Description: A double syllogism inference. For an implication-only version, see syl2im . (Contributed by NM, 31-Jan-1997)

Ref Expression
Hypotheses syl2an.1 ( 𝜑𝜓 )
syl2an.2 ( 𝜏𝜒 )
syl2an.3 ( ( 𝜓𝜒 ) → 𝜃 )
Assertion syl2an ( ( 𝜑𝜏 ) → 𝜃 )

Proof

Step Hyp Ref Expression
1 syl2an.1 ( 𝜑𝜓 )
2 syl2an.2 ( 𝜏𝜒 )
3 syl2an.3 ( ( 𝜓𝜒 ) → 𝜃 )
4 1 3 sylan ( ( 𝜑𝜒 ) → 𝜃 )
5 2 4 sylan2 ( ( 𝜑𝜏 ) → 𝜃 )