6.1.1910
NEGATE
 
CORE
 
( n1 -- n2 )

Negate n1, giving its arithmetic inverse n2.

See:
6.1.1720 INVERT, 6.1.0270 0=.

Testing:
T{  0 NEGATE ->  0 }T
T{  1 NEGATE -> -1 }T
T{ -1 NEGATE ->  1 }T
T{  2 NEGATE -> -2 }T
T{ -2 NEGATE ->  2 }T