Englishfor English speakers
invariant
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adjective
unaffected by a designated operation or transformation
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noun
a feature (quantity or property or function) that remains unchanged when a particular transformation is applied to it
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adjective
(= constant, unvarying)
unvarying in nature
maintained a constant temperature
principles of unvarying validity
expression
Noun
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An expression is a group of words, like a phrase or sentence, often one that is used by many people.
"Read between the lines" is a common expression for knowing meanings that are not written or spoken.
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An expression is a group of numbers and variables.
The expression "2x + y - 3" was set equal eight in the equation.