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Description: Cancellation law for group subtraction. ( nnncan1 analog.) (Contributed by NM, 7-Apr-2015)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | ablnncan.b | ⊢ 𝐵 = ( Base ‘ 𝐺 ) | |
| ablnncan.m | ⊢ − = ( -g ‘ 𝐺 ) | ||
| ablnncan.g | ⊢ ( 𝜑 → 𝐺 ∈ Abel ) | ||
| ablnncan.x | ⊢ ( 𝜑 → 𝑋 ∈ 𝐵 ) | ||
| ablnncan.y | ⊢ ( 𝜑 → 𝑌 ∈ 𝐵 ) | ||
| ablsub32.z | ⊢ ( 𝜑 → 𝑍 ∈ 𝐵 ) | ||
| Assertion | ablnnncan1 | ⊢ ( 𝜑 → ( ( 𝑋 − 𝑌 ) − ( 𝑋 − 𝑍 ) ) = ( 𝑍 − 𝑌 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ablnncan.b | ⊢ 𝐵 = ( Base ‘ 𝐺 ) | |
| 2 | ablnncan.m | ⊢ − = ( -g ‘ 𝐺 ) | |
| 3 | ablnncan.g | ⊢ ( 𝜑 → 𝐺 ∈ Abel ) | |
| 4 | ablnncan.x | ⊢ ( 𝜑 → 𝑋 ∈ 𝐵 ) | |
| 5 | ablnncan.y | ⊢ ( 𝜑 → 𝑌 ∈ 𝐵 ) | |
| 6 | ablsub32.z | ⊢ ( 𝜑 → 𝑍 ∈ 𝐵 ) | |
| 7 | ablgrp | ⊢ ( 𝐺 ∈ Abel → 𝐺 ∈ Grp ) | |
| 8 | 3 7 | syl | ⊢ ( 𝜑 → 𝐺 ∈ Grp ) |
| 9 | 1 2 | grpsubcl | ⊢ ( ( 𝐺 ∈ Grp ∧ 𝑋 ∈ 𝐵 ∧ 𝑍 ∈ 𝐵 ) → ( 𝑋 − 𝑍 ) ∈ 𝐵 ) |
| 10 | 8 4 6 9 | syl3anc | ⊢ ( 𝜑 → ( 𝑋 − 𝑍 ) ∈ 𝐵 ) |
| 11 | 1 2 3 4 5 10 | ablsub32 | ⊢ ( 𝜑 → ( ( 𝑋 − 𝑌 ) − ( 𝑋 − 𝑍 ) ) = ( ( 𝑋 − ( 𝑋 − 𝑍 ) ) − 𝑌 ) ) |
| 12 | 1 2 3 4 6 | ablnncan | ⊢ ( 𝜑 → ( 𝑋 − ( 𝑋 − 𝑍 ) ) = 𝑍 ) |
| 13 | 12 | oveq1d | ⊢ ( 𝜑 → ( ( 𝑋 − ( 𝑋 − 𝑍 ) ) − 𝑌 ) = ( 𝑍 − 𝑌 ) ) |
| 14 | 11 13 | eqtrd | ⊢ ( 𝜑 → ( ( 𝑋 − 𝑌 ) − ( 𝑋 − 𝑍 ) ) = ( 𝑍 − 𝑌 ) ) |