Theorem psstrd 4068

Description: Proper subclass inclusion is transitive. Deduction form of psstr 4065. (Contributed by David Moews, 1-May-2017.)

Hypotheses

Ref	Expression
psstrd.1	⊢ (𝜑 → 𝐴 ⊊ 𝐵)
psstrd.2	⊢ (𝜑 → 𝐵 ⊊ 𝐶)

Assertion

Ref	Expression
psstrd	⊢ (𝜑 → 𝐴 ⊊ 𝐶)

Proof of Theorem psstrd

Step	Hyp	Ref	Expression
1		psstrd.1	. 2 ⊢ (𝜑 → 𝐴 ⊊ 𝐵)
2		psstrd.2	. 2 ⊢ (𝜑 → 𝐵 ⊊ 𝐶)
3		psstr 4065	. 2 ⊢ ((𝐴 ⊊ 𝐵 ∧ 𝐵 ⊊ 𝐶) → 𝐴 ⊊ 𝐶)
4	1, 2, 3	syl2anc 596	1 ⊢ (𝜑 → 𝐴 ⊊ 𝐶)

This proof depends on syntax axioms:   → wi 4   ⊊ wpss 3909

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-9 2156  ax-ext 2738

This proof depends on definitions:  df-bi 210  df-an 402  df-ex 1813  df-cleq 2758  df-ne 2962  df-ss 3925  df-pss 3928

This theorem is used by: (None)