Subdirectly Irreducible Residuated Semilattices and Positive Universal Classes

CRS(fc) denotes the variety of commutative residuated semilattice-ordered monoids that satisfy (x ⋀ e)^k ≤ (x ⋀ e)^k+1. A structural characterization of the subdi-rectly irreducible members of CRS(k) is proved, and is then used to provide a constructive approach to the axiomatization of varieties generated by positive universal subclasses of CRS(k). Dedicated to the memory of Willem Johannes Blok     

Expansion and Contraction of Finite States

We present a theory that copes with the dynamics of inconsistent information. A method is set forth to represent possibly inconsistent information by a finite state. Next, finite operations for expansion and contraction of finite states are given. No extra-logical element — a choice function or an ordering over (sets of) sentences — is presupposed in the definition of contraction. Moreover, expansion and contraction are each other's duals. AGM-style characterizations of these operations follow.     

Sex comparisons of the bilateral deficit in proximal and distal upper body limb muscles

Bilateral deficit (BLD) describes a phenomenon that the force produced during maximal simultaneous bilateral contraction is lower than the sum of those produced unilaterally. The aim of this study was to examine the potential sex-related differences in BLD in upper body proximal and distal limb muscles. Ten men and eight women performed single-joint maximal contractions with their elbow flexors and index finger abductors at separate laboratory visits, during which the maximal isometric voluntary contractions (MVICs) were performed unilaterally and bilaterally with a randomized order in the designated muscle group. Surface electromyographic (EMG) signals were recorded from the prime movers of the designated muscle groups (biceps brachii and first dorsal interosseous) during the maximal contractions. Both men and women demonstrated BLD in their elbow flexors (deficit: men = −11.0 ± 6.3%; women = −10.2 ± 5.0%). Accompanied by this force deficit was the reduced EMG amplitude from the dominant biceps brachii (collapsed across sex: p = 0.045). For the index finger abductors, only men (deficit = −13.7 ± 6.1%), but not women showed BLD. Our results suggested that the BLD in the proximal muscle group is likely induced by the decreased maximal muscle activity from the dominant prime mover. The absence of BLD in women’s index finger muscle is largely due to the inter-subject variability possibly related to the sex hormone flux and unique levels of interhemispheric inhibition.     

Counterexamples to Recovery and the Filtering Condition

David Makinson has argued that the compelling character of counterexamples to the Recovery Condition on contraction is due to an appeal to justificational structure. In “naked theories” where such structure is ignored or is not present, Recovery does apply. This note attempts to show that Makinson is mistaken on both counts. Recovery fails when no appeal is made to justificational structure. This revised version was published online in August 2006 with corrections to the Cover Date.