What ⟏ means
It marks a maximum operation over a box-shaped region. In mathematical morphology (math for image shapes), it represents max-product, dilation (expanding image regions), and additive-maximum operations; surrounding definitions set the exact algebra.
⟏ pairs with , the squared logical AND or box-min operator. The paired marks appeared in 1980s technical reports for the U.S. Air Force, DARPA (the U.S. Defense Advanced Research Projects Agency), and the Department of Defense. Their first attestation is 1987. Later publications by SPIE, an optics and photonics society, also used them. APL, a mathematical programming language, has visually similar operators in a different notation.
Part of the collection
Related characters
1
Questions people ask
1Why does ⟏ show as a box?
The font or app may lack the glyph. Broader math coverage or font fallback can display it; a missing box does not make the character invalid.
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10
How to type or find ⟏
- Also called
- box max
- Search it as
- morphological dilation · max operator
- Shows up in
- Anything that takes text · its shape is whatever your font draws
⟏\27CFCodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.