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SUPPLEMENTARY MATERIAL (USERS' MATHBOXES)
Mathbox for Steven Nguyen
Structures
pwselbasr
Metamath Proof Explorer
Description: The reverse direction of pwselbasb : a function between the index and
base set of a structure is an element of the structure power.
(Contributed by SN , 29-Jul-2024)
Ref
Expression
Hypotheses
pwselbasr.y
⊢ Y = R ↑ 𝑠 I
pwselbasr.b
⊢ B = Base R
pwselbasr.v
⊢ V = Base Y
pwselbasr.r
⊢ φ → R ∈ W
pwselbasr.i
⊢ φ → I ∈ Z
pwselbasr.x
⊢ φ → X : I ⟶ B
Assertion
pwselbasr
⊢ φ → X ∈ V
Proof
Step
Hyp
Ref
Expression
1
pwselbasr.y
⊢ Y = R ↑ 𝑠 I
2
pwselbasr.b
⊢ B = Base R
3
pwselbasr.v
⊢ V = Base Y
4
pwselbasr.r
⊢ φ → R ∈ W
5
pwselbasr.i
⊢ φ → I ∈ Z
6
pwselbasr.x
⊢ φ → X : I ⟶ B
7
1 2 3
pwselbasb
⊢ R ∈ W ∧ I ∈ Z → X ∈ V ↔ X : I ⟶ B
8
4 5 7
syl2anc
⊢ φ → X ∈ V ↔ X : I ⟶ B
9
6 8
mpbird
⊢ φ → X ∈ V