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Description: Define a convenience function that "reduces" a fraction to lowest terms. Note that in this form, it is not obviously a function; we prove this in nqerf . (Contributed by NM, 27-Aug-1995) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-erq | ⊢ [Q] = ( ~Q ∩ ( ( N × N ) × Q ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | cerq | ⊢ [Q] | |
| 1 | ceq | ⊢ ~Q | |
| 2 | cnpi | ⊢ N | |
| 3 | 2 2 | cxp | ⊢ ( N × N ) |
| 4 | cnq | ⊢ Q | |
| 5 | 3 4 | cxp | ⊢ ( ( N × N ) × Q ) |
| 6 | 1 5 | cin | ⊢ ( ~Q ∩ ( ( N × N ) × Q ) ) |
| 7 | 0 6 | wceq | ⊢ [Q] = ( ~Q ∩ ( ( N × N ) × Q ) ) |