RDF.XSD.Numeric.divide

You're seeing just the function divide, go back to RDF.XSD.Numeric module for more information.

Divides two numeric literals.

For xsd:float and xsd:double operands, floating point division is performed as specified in [IEEE 754-2008]. A positive number divided by positive zero returns INF. A negative number divided by positive zero returns -INF. Division by negative zero returns -INF and INF, respectively. Positive or negative zero divided by positive or negative zero returns NaN. Also, INF or -INF divided by INF or -INF returns NaN.

If one of the given arguments is not a numeric literal or a value which can be coerced into a numeric literal, nil is returned.

nil is also returned for xsd:decimal and xsd:integer operands, if the divisor is (positive or negative) zero.

see http://www.w3.org/TR/xpath-functions/#func-numeric-divide