Erf

Definitions

  • Webster's Revised Unabridged Dictionary
    • n Erf A garden plot, usually about half an acre.
    • ***
Century Dictionary and Cyclopedia
    • n erf Inheritance; patrimony; specifically, stock; cattle.
    • n erf [D. erf.] In Cape Colony, some parts of the State of New York, and other regions originally settled by the Dutch, a small inherited house-and-garden lot in a village or settlement.
    • ***
Chambers's Twentieth Century Dictionary
    • n Erf erf a garden-plot in South Africa.
    • ***

Etymology

Webster's Revised Unabridged Dictionary
D
Chambers's Twentieth Century Dictionary
Dut.

Usage

In literature:

I bin in 'ere 'bout erf an hour, I hev, and ain't seed nowt so fur!
"Punch, or the London Charivari, Volume 103, December 10, 1892" by Various
One erf us better take a look through that young stock in the lower field, too, and see if there's any more sign uh blackleg.
"Sawtooth Ranch" by B. M. Bower
Prue had just time to seize a bite before she went to dress for a frankly confessed dancing-bout at Eliza Erf's.
"In a Little Town" by Rupert Hughes
***

In news:

Shares of ERF Now Oversold.
In trading on Friday, shares of Enerplus Corp (NYSE: ERF ) entered into oversold territory, changing hands as low as $12.72 per share.
This morning, Enerplus ( ERF ) declared its monthly dividend of 9 cents per share, maintaining the amount paid to shareholders last month.
ERF Stock Crowded With Sellers.
In trading on Friday, shares of Enerplus Corp (NYSE: ERF ) entered into oversold territory, changing hands as low as $13.32 per share.
In trading on Wednesday, shares of Enerplus Corp (NYSE: ERF ) entered into oversold territory, changing hands as low as $21.10 per share.
Manassas, VA – ERF , based in Germany, will receive the NRB International Television Ministry Award during the February 21st International Keynote Session at the NRB 2012 Convention & Exposition.
Nexus One packs both ETF, ERF .
***

In science:

This is Question 8 in , although it dates back to the paper where it is shown that a finitely generated virtually soluble group which is ERF must be virtually polycyclic.
Strictly ascending HNN extensions in soluble groups
To further illustrate the problem, the class of ERF groups is closed under taking quotients and subgroups, but no member can contain a nonabelian free group.
Strictly ascending HNN extensions in soluble groups
Thus a new finitely generated ERF group would not be elementary amenable but nor could it contain a non-abelian free group, and even residually finite examples of this are hard to come by.
Strictly ascending HNN extensions in soluble groups
Another property that is considerably stronger than residual finiteness but weaker than ERF is that of being locally extended residual finite or LERF.
Strictly ascending HNN extensions in soluble groups
This is when every finitely generated subgroup is the intersection of finite index subgroups and is sometimes called subgroup separable (although the phrase subgroup separable originally referred to ERF, as can be seen in older papers).
Strictly ascending HNN extensions in soluble groups
LERF property is closed under taking subgroups as well as finite index supergroups (for the latter claim see Lemma 4.2, which establishes this for ERF and the proof generalises immediately for LERF).
Strictly ascending HNN extensions in soluble groups
Here erf (x) is the error function defined in Eq. (4.37).
Charged Particle Motion in a Plasma: Electron-Ion Energy Partition
S ≡ (tJ − tJ,ini − 3dini )/√3 and erf (x) is the error function.
Reheating after f(R) inflation
P re(M F (A, w)) ∼= RH omC[x] (P erf (C), P erf (A)) the category of colimit preserving functors[To¨e].
Curved String Topology and Tangential Fukaya Categories II
This category of functors is acted upon the category RH omC[x] (P erf (C), P erf (C) by convolution.
Curved String Topology and Tangential Fukaya Categories II
Df in (C[α]/α2 ) ∼= P erf (C[[t]]) The aforementioned C[[t]](degree t = −2n) linear structure now arises in view of the natural equivalence between (idempotent complete, pre-triangulated) module categories over P erf (C[[t]]) and ordinary C[[t]]-linear, (idempotent complete, pre-triangulated) dg categories.
Curved String Topology and Tangential Fukaya Categories II
RH omC[x] (P erf (C[x]), P erf (A)) → RH omC[x] (P erf (C), P erf (A)) In view of the fact that i∗ ◦ i∗(N ) ∼= C ⊗C[x] N , and the fact that N and C are perfect over A and C[x] respectively, it follows that i∗ ◦ i∗ (N ) is perfect over A0 .
Curved String Topology and Tangential Fukaya Categories II
A (φ) + t(φ ◦ e ∧ +e ∧ ◦φ)) The differential dA denotes the differential on H omP erf (A) (M , N ).
Curved String Topology and Tangential Fukaya Categories II
M F (A, w)] ∼= [P re(M F (A, w))]/[P erf (A0 )] It is often convenient to work with the formal Ind-completion I nd(M F (A, w)) which we shall denote by M F ∞ (A, w).
Curved String Topology and Tangential Fukaya Categories II
The error function is used whenever the parameter z connected to χ 2 variations assumes always positive values. It may be noted that erf(z) can be derived from Φ(z).
A Review Study of NIST Statistical Test Suite: Development of an indigenous Computer Package
***