Description: Relationship between subtraction and negative. Theorem I.3 of Apostol p. 18. (Contributed by Mario Carneiro, 27-May-2016)
Ref | Expression | ||
---|---|---|---|
Hypotheses | negidd.1 | |
|
pncand.2 | |
||
Assertion | negsubd | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | negidd.1 | |
|
2 | pncand.2 | |
|
3 | negsub | |
|
4 | 1 2 3 | syl2anc | |