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Description: Cancellation law for addition. Theorem I.1 of Apostol p. 18. (Contributed by NM, 14-May-2003) (Revised by Scott Fenton, 3-Jan-2013)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | mul.1 | ⊢ 𝐴 ∈ ℂ | |
| mul.2 | ⊢ 𝐵 ∈ ℂ | ||
| mul.3 | ⊢ 𝐶 ∈ ℂ | ||
| Assertion | addcan2i | ⊢ ( ( 𝐴 + 𝐶 ) = ( 𝐵 + 𝐶 ) ↔ 𝐴 = 𝐵 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | mul.1 | ⊢ 𝐴 ∈ ℂ | |
| 2 | mul.2 | ⊢ 𝐵 ∈ ℂ | |
| 3 | mul.3 | ⊢ 𝐶 ∈ ℂ | |
| 4 | addcan2 | ⊢ ( ( 𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ ∧ 𝐶 ∈ ℂ ) → ( ( 𝐴 + 𝐶 ) = ( 𝐵 + 𝐶 ) ↔ 𝐴 = 𝐵 ) ) | |
| 5 | 1 2 3 4 | mp3an | ⊢ ( ( 𝐴 + 𝐶 ) = ( 𝐵 + 𝐶 ) ↔ 𝐴 = 𝐵 ) |