1,968 research outputs found
A construction of infinite sets of intertwines for pairs of matroids
An intertwine of a pair of matroids is a matroid such that it, but none of
its proper minors, has minors that are isomorphic to each matroid in the pair.
For pairs for which neither matroid can be obtained, up to isomorphism, from
the other by taking free extensions, free coextensions, and minors, we
construct a family of rank-k intertwines for each sufficiently large integer k.
We also treat some properties of these intertwines.Comment: 11 page
Transversal Lattices
A flat of a matroid is cyclic if it is a union of circuits; such flats form a
lattice under inclusion and, up to isomorphism, all lattices can be obtained
this way. A lattice is a Tr-lattice if all matroids whose lattices of cyclic
flats are isomorphic to it are transversal. We investigate some sufficient
conditions for a lattice to be a Tr-lattice; a corollary is that distributive
lattices of dimension at most two are Tr-lattices. We give a necessary
condition: each element in a Tr-lattice has at most two covers. We also give
constructions that produce new Tr-lattices from known Tr-lattices.Comment: 12 pages; 5 figure
An integrated circuit switch
Multi-chip integrated circuit switch consists of a GaAs photon-emitting diode in close proximity with S1 phototransistor. A high current gain is obtained when the transistor has a high forward common-emitter current gain
Lattice path matroids: the excluded minors
A lattice path matroid is a transversal matroid for which some collection of
incomparable intervals in some linear order on the ground set is a
presentation. We characterize the minor-closed class of lattice path matroids
by its excluded minors.Comment: 13 pages, 2 figure
Photon-coupled isolation switch Quarterly report, 1 Jan. - 31 Mar. 1967
Design, development, and testing of new integrated circuit switch devic
Photon-coupled isolation switch Quarterly report, 1 Oct. - 31 Dec. 1966
Integrated circuit photon coupled isolation switc
Photon-coupled isolation switch Quarterly report, 1 Jul. - 30 Sep. 1966
Integrated circuit isolation switch using photon couplin
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