The Mathematical Operators block has sixteen variation sequences defined for standardized variants.[3][4] They use U+FE00 VARIATION SELECTOR-1 (VS01) to denote variant symbols (depending on the font):
Variation sequences
Base character
Base
+VS01
Description
U+2205 EMPTY SET
∅
∅︀
zero with long diagonal stroke overlay form
U+2229 INTERSECTION
∩
∩︀
with serifs
U+222A UNION
∪
∪︀
with serifs
U+2268 LESS-THAN BUT NOT EQUAL TO
≨
≨︀
with vertical stroke
U+2269 GREATER-THAN BUT NOT EQUAL TO
≩
≩︀
with vertical stroke
U+2272 LESS-THAN OR EQUIVALENT TO
≲
≲︀
following the slant of the lower leg
U+2273 GREATER-THAN OR EQUIVALENT TO
≳
≳︀
following the slant of the lower leg
U+228A SUBSET OF WITH NOT EQUAL TO
⊊
⊊︀
with stroke through bottom members
U+228B SUPERSET OF WITH NOT EQUAL TO
⊋
⊋︀
with stroke through bottom members
U+2293 SQUARE CAP
⊓
⊓︀
with serifs
U+2294 SQUARE CUP
⊔
⊔︀
with serifs
U+2295 CIRCLED PLUS
⊕
⊕︀
with white rim
U+2297 CIRCLED TIMES
⊗
⊗︀
with white rim
U+229C CIRCLED EQUALS
⊜
⊜︀
with equal sign touching the circle
U+22DA LESS-THAN EQUAL TO OR GREATER-THAN
⋚
⋚︀
with slanted equal
U+22DB GREATER-THAN EQUAL TO OR LESS-THAN
⋛
⋛︀
with slanted equal
History
The following Unicode-related documents record the purpose and process of defining specific characters in the Mathematical Operators block:
Suignard, Michel (2001-09-10), "T.9 B.1 List of combining characters/Variation selectors", Comments accompanying the US positive vote on the FPDAM 1 to ISO/IEC 10646-1:2001
Umamaheswaran, V. S. (2007-07-26), "M50.7 (Math symbol glyph correction) [U+22C4]", Unconfirmed minutes of WG 2 meeting 50, Frankfurt-am-Main, Germany; 2007-04-24/27
Constable, Peter (2024-07-29), "Section 20. Middle Asterisk", UTC #180 Minutes, Consider adding an annotation to U+2217 that it may be used to represent the telephony asterisk