Less-than sign

For the use of the "<" sign as punctuation, seeBracket § Angle brackets.

Theless-than signis a mathematical symbol that denotes aninequalitybetween two values. The widely adopted form of two equal-length strokes connecting in anacute angleat the left,<,has been found in documents dated as far back as the 1560s. In mathematical writing, the less-than sign is typically placed between two values being compared and signifies that the first number is less than the second number. Examples of typical usage include1⁄2< 1and−2 < 0.

<
Less-than sign
InUnicode	U+003C<LESS-THAN SIGN(&lt;, &LT;)
Different from
Different from	U+2329〈LEFT-POINTING ANGLE BRACKET
Related
See also	U+003E>GREATER-THAN SIGN U+2264≤LESS-THAN OR EQUAL TO U+2A7D⩽LESS-THAN OR SLANTED EQUAL TOused e.g. in Poland U+226E≮NOT LESS-THAN U+226A≪MUCH LESS-THAN

Since the development of computerprogramming languages,the less-than sign and thegreater-than signhave been repurposed for a range of uses and operations.

Computing

Theless-than sign,<,is an originalASCIIcharacter (hex 3C, decimal 60).

Programming

InBASIC,Lisp-family languages, andC-family languages (includingJavaandC++),comparison operator<means "less than".

InColdfusion,operator.lt.means "less than".

InFortran,operator.LT.means "less than"; later versions allow<.

Shell scripts

InBourne shell(and many other shells), operator-ltmeans "less than". Less-than sign is used toredirectinput from a file. Less-than plus ampersand (<&) is used to redirect from afile descriptor.

Double less-than sign

Thedouble less-than sign,<<,may be used for an approximation of themuch-less-than sign(≪) or of the openingguillemet(«). ASCII does not encode either of these signs, though they are both included inUnicode.

InBash,Perl,andRuby,operator<<EOF(where "EOF" is an arbitrary string, but commonly "EOF" denoting "end of file" ) is used to denote the beginning of ahere document.

InCandC++,operator<<represents abinary left shift.

In theC++ Standard Library,operator<<,when applied on an output stream, acts asinsertion operatorand performs an output operation on the stream.

InRuby,operator<<acts asappend operatorwhen used between an array and the value to be appended.

InXPaththe<<operator returns true if the left operand precedes the right operand in document order; otherwise it returns false.

Triple less-than sign

InPHP,operator<<<OUTPUTis used to denote the beginning of aheredocstatement (whereOUTPUTis an arbitrary named variable.)

In Bash,<<<wordis used as a "here string", wherewordis expanded and supplied to the command on its standard input, similar to a heredoc.

Less-than sign with equals sign

The less-than sign with the equals sign,<=,may be used for an approximation of theless-than-or-equal-to sign,≤.ASCII does not have a less-than-or-equal-to sign, butUnicodedefines it at code point U+2264.

InBASIC,Lisp-family languages, andC-family languages (includingJavaandC++), operator<=means "less than or equal to". InSinclair BASICit is encoded as a single-byte code point token.

InProlog,=<means "less than or equal to" (as distinct from the arrow<=).

InFortran,operators.LE.and<=both mean "less than or equal to".

InBourne shellandWindows PowerShell,the operator-lemeans "less than or equal to".

Less-than sign with hyphen-minus

In theR programming language,the less-than sign is used in conjunction with ahyphen-minusto create an arrow (<-), this can be used as the left assignment operator.

Spaceship operator

Less-than sign is used in thespaceship operator.

HTML

InHTML(andSGMLandXML), the less-than sign is used at the beginning of tags. The less-than sign may be included with<.The less-than-or-equal-to sign,≤,may be included with≤.

Unicode

Unicodeprovides various Less Than Symbol:

Symbol	Name	Code Point
⍃	Apl Functional Symbol Quad Less Than	U+2343
⧀	Circled Less Than	U+29C0
⦖	Double Right Arc Less Than Bracket	U+2996
＜	Fullwidth less than	U+FF1C
⋜	Equal To Or Less Than	U+22DC
⦓	Left Arc Less Than Bracket	U+2993
⥷	Leftwards Arrow Through Less Than	U+2977
⥶	Less Than Above Leftwards Arrow	U+2976
≨	Less Than But Not Equal To	U+2268
⋦	Less Than But Not Equivalent To	U+22E6
≤	Less Than Or Equal To	U+2264
≲	Less Than Or Equivalent To	U+2272
≦	Less Than Over Equal To	U+2266
<	Less Than Sign	U+003C
⩹	Less Than With Circle Inside	U+2A79
⋖	Less Than With Dot	U+22D6
≪	Much Less Than	U+226A
≰	Neither Less Than Nor Equal To	U+2270
≴	Neither Less Than Nor Equivalent To	U+2274
≮	Not Less Than	U+226E
﹤	Small Less Than Sign	U+FE64
⋘	Very Much Less Than	U+22D8

The less-than sign may be seen for an approximation of the openingangle bracket,⟨.True angle bracket characters, as required inlinguistics notation,are expected in formal texts.

Mathematics

In an inequality, the less-than sign and greater-than sign always "point" to the smaller number. Put another way, the "jaws" (the wider section of the symbol) always direct to the larger number.

The less-than-sign is sometimes used to represent atotal order,partial orderorpreorder.However, the symbol$\prec$is often used when it would be confusing or not convenient to use<.In mathematical writing usingLaTeX,theTeXcommand is\prec.The Unicodecode pointisU+227A≺PRECEDES.

See also

• Inequality (mathematics)
• Greater-than sign
• Relational operator
• Much-less-than sign