Assuming
✖
Assuming
evaluates expr with assum appended to $Assumptions, so that assum is included in the default assumptions used by functions such as Refine, Simplify, and Integrate.
Details

- Assuming affects the default assumptions for all functions that have an Assumptions option.
- The assumptions can be equations, inequalities, or domain specifications, or lists or logical combinations of these.
- Assumptions from nested invocations of Assuming are combined.
- Assuming[assum,expr] is effectively equivalent to Block[{$Assumptions=$Assumptions&&assum},expr].
- Assuming converts lists of assumptions {a1,a2,…} to a1&&a2&&….
Examples
open allclose allBasic Examples (2)Summary of the most common use cases
Scope (3)Survey of the scope of standard use cases
Specify assumptions for simplifiers:

https://wolfram.com/xid/0ldhq4y-b9hoth

https://wolfram.com/xid/0ldhq4y-eq8izc

Specify assumptions for Integrate and in integral transforms:

https://wolfram.com/xid/0ldhq4y-11osd

Specify assumptions for Limit and Series:

https://wolfram.com/xid/0ldhq4y-iplxsp

Applications (1)Sample problems that can be solved with this function
Write code that uses assumptions; find the number of real roots of a x2+b x+c:

https://wolfram.com/xid/0ldhq4y-6rorc

https://wolfram.com/xid/0ldhq4y-hb8fd9


https://wolfram.com/xid/0ldhq4y-rtve


https://wolfram.com/xid/0ldhq4y-e0wzh2

Properties & Relations (5)Properties of the function, and connections to other functions
Assuming locally sets the value of $Assumptions:

https://wolfram.com/xid/0ldhq4y-b09veq

Assumptions from nested invocations of Assuming are combined:

https://wolfram.com/xid/0ldhq4y-iqexaa

Block can also be used to locally set the value of $Assumptions:

https://wolfram.com/xid/0ldhq4y-duzrhj

Here the assumptions from Assuming are not used inside Block:

https://wolfram.com/xid/0ldhq4y-e0ud4o

This is equivalent to using nested Assuming:

https://wolfram.com/xid/0ldhq4y-f4d9f8

Assuming affects functions using the Assumptions :> $Assumptions option setting:

https://wolfram.com/xid/0ldhq4y-go5sme

For some functions assumptions can be given both as an argument and as an option value:

https://wolfram.com/xid/0ldhq4y-d7eor0

Possible Issues (1)Common pitfalls and unexpected behavior
When Assumptions option is set directly, assumptions specified with Assuming are not used:

https://wolfram.com/xid/0ldhq4y-fj4acx

Wolfram Research (2003), Assuming, Wolfram Language function, https://reference.wolfram.com/language/ref/Assuming.html.
Text
Wolfram Research (2003), Assuming, Wolfram Language function, https://reference.wolfram.com/language/ref/Assuming.html.
Wolfram Research (2003), Assuming, Wolfram Language function, https://reference.wolfram.com/language/ref/Assuming.html.
CMS
Wolfram Language. 2003. "Assuming." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/Assuming.html.
Wolfram Language. 2003. "Assuming." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/Assuming.html.
APA
Wolfram Language. (2003). Assuming. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/Assuming.html
Wolfram Language. (2003). Assuming. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/Assuming.html
BibTeX
@misc{reference.wolfram_2025_assuming, author="Wolfram Research", title="{Assuming}", year="2003", howpublished="\url{https://reference.wolfram.com/language/ref/Assuming.html}", note=[Accessed: 05-June-2025
]}
BibLaTeX
@online{reference.wolfram_2025_assuming, organization={Wolfram Research}, title={Assuming}, year={2003}, url={https://reference.wolfram.com/language/ref/Assuming.html}, note=[Accessed: 05-June-2025
]}