The diagonal slash "/" used as the bar between numerator and denominator of an in-line fraction (Bringhurst 1997, p. 284). The solidus is also called a diagonal.
Special care is needed when interpreting the meaning of a solidus in in-line math because of the notational ambiguity in expressions such as 
. Whereas in many textbooks, "
" is intended to denote 
, taken literally or evaluated in a symbolic mathematics
languages such as the Wolfram Language,
it means 
. For clarity, parentheses
should therefore always be used when delineating compound denominators.
Common examples of failure to parenthesize include 
(where 
is energy, 
is Boltzmann's constant, and 
is temperature; Arfken 1985, p. 950), its variant 
(where 
is a constant and 
is wavelength; Weast 1981, pp. F-109 and F-111),
the exponent 
in the normal distribution (where 
is the standard deviation;
Hastings 2000, p. 217). Other miscellaneous examples occur even in the standard
references for computer math systems (e.g., Wolfram 2003, pp. 776, 779, and
787).
