Function composition and inverses
Composition feeds one output into another function; inversion requires unique preimages.
Key knowledge
The composition (f∘g)(x) is f(g(x)), defined when x belongs to g's domain and g(x) belongs to f's domain. A one-to-one function has an inverse on its actual range, reversing its input-output assignment.
Values and equations
(f∘g)(x)=f(g(x)); f⁻¹(f(x))=x; f(f⁻¹(y))=y
- f, g
- Functions with compatible domains for composition
- x
- Input in the relevant domain
- y
- Output in f's range; f one-to-one for inverse identities
Conditions and scope
- Composition generally depends on order.
- The inverse f⁻¹ is a function, not the reciprocal 1/f; restricting a domain can make a function one-to-one.
Composition defined only on compatible inputs. Inverse on the actual range; no claim every function is invertible.
Sources · 2
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Jay Abramson / OpenStax, Rice University2 sources
Evidence and review
Checked the stated function composition and inverses and restrictions against the listed primary sections; exact inspected boundaries are in the author receipt.
2026-10-10 · Independent Physics and Measurement reference editor (AI editorial bounded review). Independent AI editorial review of this entry's statements, equations, applicability conditions and source coverage. Source checks apply to these claims within their stated limits.
Entry details
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- foundation-math-composition-inverse
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- foundations-refresh.1
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