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A double-stroke rightward arrow that asserts a logical consequence in one notation and introduces a function in another.
In logic it asserts that the right-hand statement follows from the left-hand one. In JavaScript the same arrow separates a function's parameters from its body. Both are drawn as two horizontal strokes followed by an angle bracket, and the notations are otherwise unconnected.
The double-stroke rightward arrow is shared: one asserts that a statement follows from another, the other introduces a function.
Drawn from the visual attributes recorded for each symbol. Only traits the two records disagree about are listed.
| Trait | Implies sign | Arrow function notation |
|---|---|---|
| Symmetry | horizontal | none |
| Implies sign | Arrow function notation | |
|---|---|---|
| Notation | Formal logic | JavaScript and related languages |
| Left side | A statement | Parameters |
| Right side | A statement that follows | The function body |
| Also changes scope | No | Yes — it does not bind its own enclosing object |
| Relationship (from Symbolwise's records) | Commonly confused with Arrow function notation — The double-stroke rightward arrow is shared: one asserts that a statement follows from another, the other introduces a function. | Commonly confused with Implies sign — The logical implication arrow is drawn the same way; one introduces a function, the other asserts that one statement follows from another. |
Unicode Code Chart: Mathematical Operators (U+2200–U+22FF)
The Unicode Consortium · retrieved 2026-07-30
Authoritative for the character's code point, name and block only. Unicode assigns identity; it does not define what a symbol means in use.
Unicode Code Chart: Arrows (U+2190–U+21FF)
The Unicode Consortium · retrieved 2026-07-31
Authoritative for the character's code point, name and block only. Unicode assigns identity; it does not define what a symbol means in use.
Wikipedia · retrieved 2026-07-31
Tertiary reference. Used for what the notation means in ordinary mathematical practice and for attribution of its introduction, not for a claim that any body defines it.
Glossary of mathematical symbols
Wikipedia · retrieved 2026-07-31
Tertiary reference. Used for what the notation means in ordinary mathematical practice and for attribution of its introduction, not for a claim that any body defines it.
Count the arrowheads. A single head means implication: if the left statement holds then so does the right, with no claim in the other direction. Two heads mean equivalence: each statement implies the other, so they hold in exactly the same circumstances. Reading a one-way implication as though it were equivalence is the commonest error made with either symbol.
Look at the shaft and at what surrounds it. Logical implication is drawn with a doubled shaft and sits between statements; a reaction arrow has a single shaft and sits between chemical formulae, usually with conditions written above and below it. Neither is an equals sign, and both assert direction rather than equality.
Alpha is a Greek letter and stands for a quantity — an angle, a coefficient, a significance level. The proportionality sign is an operator and stands between two quantities to say they keep a constant ratio. The drawings differ in that the proportionality sign's right-hand stroke runs out in an open curve rather than closing into the letter's tail.
Look at the left-hand edge. A straight flat back is an AND gate: the output is true only when every input is. A curved concave back is an OR gate: true when any input is. Everything else about the shapes is similar, which is why the back edge is worth checking deliberately rather than at a glance.