Description: The range of a function value at a proper class is empty. (Contributed by AV, 20-Aug-2022)
Ref | Expression | ||
---|---|---|---|
Hypothesis | rnfvprc.y | ⊢ 𝑌 = ( 𝐹 ‘ 𝑋 ) | |
Assertion | rnfvprc | ⊢ ( ¬ 𝑋 ∈ V → ran 𝑌 = ∅ ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | rnfvprc.y | ⊢ 𝑌 = ( 𝐹 ‘ 𝑋 ) | |
2 | fvprc | ⊢ ( ¬ 𝑋 ∈ V → ( 𝐹 ‘ 𝑋 ) = ∅ ) | |
3 | 1 2 | eqtrid | ⊢ ( ¬ 𝑋 ∈ V → 𝑌 = ∅ ) |
4 | 3 | rneqd | ⊢ ( ¬ 𝑋 ∈ V → ran 𝑌 = ran ∅ ) |
5 | rn0 | ⊢ ran ∅ = ∅ | |
6 | 4 5 | eqtrdi | ⊢ ( ¬ 𝑋 ∈ V → ran 𝑌 = ∅ ) |