Calculus

This module contains query handlers responsible for calculus queries: infinitesimal, finite, etc.

class sympy.assumptions.handlers.calculus.AskFiniteHandler

Handler for key ‘finite’.

Test that an expression is bounded respect to all its variables.

Examples of usage:

>>> from sympy import Symbol, Q
>>> from sympy.assumptions.handlers.calculus import AskFiniteHandler
>>> from sympy.abc import x
>>> a = AskFiniteHandler()
>>> a.Symbol(x, Q.positive(x)) == None
True
>>> a.Symbol(x, Q.finite(x))
True

static Add(expr, assumptions)

Return True if expr is bounded, False if not and None if unknown.

Truth Table:

		B	U			?
			‘+’	‘-‘	‘x’	‘+’	‘-‘	‘x’
B		B	U			?
U	‘+’		U	?	?	U	?	?
	‘-‘		?	U	?	?	U	?
	‘x’		?			?
?						?

• ‘B’ = Bounded
• ‘U’ = Unbounded
• ‘?’ = unknown boundedness
• ‘+’ = positive sign
• ‘-‘ = negative sign
• ‘x’ = sign unknown

• All Bounded -> True
• 1 Unbounded and the rest Bounded -> False
• >1 Unbounded, all with same known sign -> False
• Any Unknown and unknown sign -> None
• Else -> None

When the signs are not the same you can have an undefined result as in oo - oo, hence ‘bounded’ is also undefined.

static Mul(expr, assumptions)

Return True if expr is bounded, False if not and None if unknown.

Truth Table:

	B	U	?
			s	/s
B	B	U	?
U		U	U	?
?			?

• B = Bounded
• U = Unbounded
• ? = unknown boundedness
• s = signed (hence nonzero)
• /s = not signed

static Pow(expr, assumptions)

Unbounded ** NonZero -> Unbounded Bounded ** Bounded -> Bounded Abs()<=1 ** Positive -> Bounded Abs()>=1 ** Negative -> Bounded Otherwise unknown

static Symbol(expr, assumptions)

Handles Symbol.

Examples

>>> from sympy import Symbol, Q
>>> from sympy.assumptions.handlers.calculus import AskFiniteHandler
>>> from sympy.abc import x
>>> a = AskFiniteHandler()
>>> a.Symbol(x, Q.positive(x)) == None
True
>>> a.Symbol(x, Q.finite(x))
True