Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - start with the Axiom of Extensionality
Subclasses and subsets
eqimsscd
Next ⟩
eqimss
Metamath Proof Explorer
Ascii
Unicode
Theorem
eqimsscd
Description:
Equality implies inclusion, deduction version.
(Contributed by
SN
, 15-Feb-2025)
Ref
Expression
Hypothesis
eqimssd.1
⊢
φ
→
A
=
B
Assertion
eqimsscd
⊢
φ
→
B
⊆
A
Proof
Step
Hyp
Ref
Expression
1
eqimssd.1
⊢
φ
→
A
=
B
2
ssid
⊢
A
⊆
A
3
1
2
eqsstrrdi
⊢
φ
→
B
⊆
A