U+21A0 RIGHTWARDS TWO HEADED ARROW
U+21A0 was added to Unicode in version 1.1 (1993). It belongs to the block
This character is a Math Symbol and is commonly used, that is, in no specific script. The character is also known as z notation total surjection and fast cursor right.
The glyph is not a composition. It has a Neutral East Asian Width. In bidirectional context it acts as Other Neutral and is not mirrored. The glyph can, under circumstances, be confused with 1 other glyphs. In text U+21A0 behaves as Alphabetic regarding line breaks. It has type Other for sentence and Other for word breaks. The Grapheme Cluster Break is Any.
The CLDR project labels this character “rightwards two headed arrow” for use in screen reading software. It assigns additional tags, e.g. for search in emoji pickers: rightwards two headed arrow.
The Wikipedia has the following information about this codepoint:
In mathematics, a surjective function (also known as surjection, or onto function) is a function f that maps an element x to every element y; that is, for every y, there is an x such that f(x) = y. In other words, every element of the function's codomain is the image of at least one element of its domain. It is not required that x be unique; the function f may map one or more elements of X to the same element of Y.
The term surjective and the related terms injective and bijective were introduced by Nicolas Bourbaki, a group of mainly French 20thcentury mathematicians who, under this pseudonym, wrote a series of books presenting an exposition of modern advanced mathematics, beginning in 1935. The French word sur means over or above, and relates to the fact that the image of the domain of a surjective function completely covers the function's codomain.
Any function induces a surjection by restricting its codomain to the image of its domain. Every surjective function has a right inverse assuming the axiom of choice, and every function with a right inverse is necessarily a surjection. The composition of surjective functions is always surjective. Any function can be decomposed into a surjection and an injection.
Representations
System  Representation 

Nº  8608 
UTF8  E2 86 A0 
UTF16  21 A0 
UTF32  00 00 21 A0 
URLQuoted  %E2%86%A0 
HTMLEscape  ↠ 
Wrong windows1252 Mojibake  â 
HTMLEscape  ↠ 
HTMLEscape  ↠ 
alias  z notation total surjection 
alias  fast cursor right 
L^{A}T_{E}X  \twoheadrightarrow 
Related Characters
Confusables
Elsewhere
Complete Record
Property  Value 

1.1 (1993)  
RIGHTWARDS TWO HEADED ARROW  
RIGHT TWO HEADED ARROW  
Arrows  
Math Symbol  
Common  
Other Neutral  
Not Reordered  
None  


✘  




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✘  
✘  
✘  
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None  
✘  
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✘  
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✘  
✘  
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✘  
✘  
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✘  
✘  
Neutral  
✘  
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Any  
✔  
✘  
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✘  
Not Applicable  
✘  
✘  
✘  
✘  
✘  
✘  
—  
NA  
Other  
—  
No_Joining_Group  
✘  
—  
Non Joining  
Alphabetic  
✘  
✔  
✘  
Yes  
Yes  


Yes  
Yes  
None  
not a number  
✘  
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✔  
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Other  


✘  
✘  
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R  
✘  
Other  
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