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Number & MeasureGreekEnglish

Homeomorphism

/ˌhoʊmiəˈmɔːrfɪzəm/noun

A continuous one-to-one map between topological spaces whose inverse is also continuous, making the two spaces the same for topological purposes.

The Greek roots

ὅμοιος
hómoios
similar, of like kind
+
μορφή
morphḗ
form, shape

Literally: similar-shapedness

The story of the word

The single letter separating homeomorphism from homomorphism is a real Greek distinction: ὅμοιος means similar, ὁμός means identical. Mathematicians borrowed both and gave them different jobs, one in topology and one in algebra, so mispronouncing the word changes the subject. Poincaré was using homéomorphisme in the 1890s while working out analysis situs, the field now called topology.

How it travelled
Ancient Greek → scientific coinage → English
First recorded
20th century

Same family

homoeopathymorphologyamorphousmetamorphosis

In a sentence

The old joke about the doughnut and the coffee cup is a statement that the two are homeomorphic.

Built on the same root

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