tactinvariantn.

Etymology: < Latin tactus touch + invariant adj. and n.Previous versions of the OED give the stress as: ˌtactinˈvariant.

Mathematics.

(See quots.)

ΘΚΠ

the world > relative properties > number > geometry > curve > [noun] > touching

osculation1798

tactinvariant1856

superosculation1876

osculant1879

1856 A. Cayley Coll. Math. Papers II. 320 The function which, equated to zero, expresses the result of the elimination is an invariant which (from its geometrical signification) might be termed the Tactinvariant of the two quantics.

1873 G. Salmon Treat. Higher Plane Curves (ed. 2) ix. 348 We have seen..that the order of the condition of contact of two curves u, v, or, as we shall call it, of their tact-invariant, is in the coeefficients of v..; and..in the coefficients of u.

1879 G. Salmon Treat. Higher Plane Curves (ed. 3) iii. 80 The condition that two curves U, V, should touch (which condition is called their tact-invariant).

This entry has not yet been fully updated (first published 1910; most recently modified version published online June 2019).

单词	tactinvariant
释义	tactinvariantn. Etymology: < Latin tactus touch + invariant adj. and n.Previous versions of the OED give the stress as: ˌtactinˈvariant. Mathematics. (See quots.) ΘΚΠ the world > relative properties > number > geometry > curve > [noun] > touching osculation1798 tactinvariant1856 superosculation1876 osculant1879 1856 A. Cayley Coll. Math. Papers II. 320 The function which, equated to zero, expresses the result of the elimination is an invariant which (from its geometrical signification) might be termed the Tactinvariant of the two quantics. 1873 G. Salmon Treat. Higher Plane Curves (ed. 2) ix. 348 We have seen..that the order of the condition of contact of two curves u, v, or, as we shall call it, of their tact-invariant, is in the coeefficients of v..; and..in the coefficients of u. 1879 G. Salmon Treat. Higher Plane Curves (ed. 3) iii. 80 The condition that two curves U, V, should touch (which condition is called their tact-invariant). This entry has not yet been fully updated (first published 1910; most recently modified version published online June 2019). < n.1856
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