DISCONTINUOUS FUNCTIONS. 245 



this sense they become perfectly intelligible; thus 

 a + b generally denotes, that whatever may be the 

 interpretation of the quantities represented by 

 the symbols a and b ; the quantity represented 

 by a must be added to the quantity represented 

 by b. The analyst, in accordance with his general 

 views, attaches another idea to the symbols a -\- b; 

 he no longer regards a + b as denoting an opera- 

 tion, but considers the quantity thus symbolized 

 as a simple one, upon which he may perform other 

 operations to aid him in his investigations. The 

 same remark will equally apply to the other signs 



of operations (a - b), ab, j, to each of which 



we may attach the general idea of abstract mag- 

 nitude, besides that of their common intepretation. 

 Now, the "> placed between two quantities denotes 

 their difference, and is quite distinct from either 

 of the signs of operation -1- and — ; since it does 

 not denote any operation, but simply an abstract 

 quantity, which is, the quantity that one magni- 

 tude exceeds that of another. The operations 

 denoted by + and — have an equal power to 

 assist us in obtaining the value a <« cr, which repre- 

 sents (a - ,v) when a > {v, and (- a + .v) when 

 n < X. 



